The key bit may be the term “Classical” and, perhaps, the location. Academics of the post-classical period have recent publications about the cenote at Chichén Itzá, indicating that the people sacrificed came from a wide geographical area, Copan or western Honduras, “Copan or Tula of the Central Highlands in Mexico, just across the Yucatan Peninsula” https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.23879

The article is informative, but be aware that it’s not lacking on details of what the bones themselves relate.

This older, 2015, piece “A Brief Note on Human Sacrifice in Classical Mayan Culture” examines human sacrifice in the Classical period. https://sites.psu.edu/kerenw/?p=142. Likewise this one, “Human Sacrificial Rites Among the Maya of Mayapán: A Bioarchaeological Perspective” looking at the post classical period. https://link.springer.com/chapter/10.1007/978-0-387-48871-4_10

I’d tend to say that it’s not settled.

I think I understand where Graham is coming from, even though it can seem counterintuitive to most readers. First, I'd like to point out that she is not the only academic to challenge the notion of Mesoamerican human sacrifice. In 'When Montezuma met Cortes,' Matthew Restall refuses to call Aztec sacrifice sacrifice, instead describing the practise as 'ritual slayings.' To be honest, I'm not sure if this is that much better, but coming up with new terminology is going to be an involved process, so let's give it some time. So, the question is, why have these scholars started to move away from the term?

Well, the main problem is that 'human sacrifice,' as it is conceived and articulated, comes out of a western historical tradition, not a Mesoamerican one. Human sacrifices are associated with devil worship, sacrilege against Christian religious sites and objects, and of course, expressions of female sexuality. It has been a long-time since I've read anything about European witchcraft and heresy, but I do distinctly remember reading about the Devil's 'frigid member,' and what he supposedly did with it. Incidentally, this is one part of the sacrifice story that remains prevalent in modern fiction that depicts human sacrifice. A good example may be King Kong, where the expeditions female (in white of course) is to be offered to King Kong, and she has to be rescued by the male protagonists (IIRC, haven't seen it in a while). Temple of Doom also has this dynamic. Add to the conflict the racial element, and we have a group of brown people taking a white virgin away from a white male and we start to see why the term 'Human Sacrifice' may be a little problematic.

Of course, none of these associations really capture how the act of offering humans was conceived and carried out in Mesoamerica. They did not worship the devil, nor desecrate any Christian spaces (the opposite would ultimately occur), and the racial element is completely divorced from the reality. This is the problem with the term, it divorces the reality of human offerings from the rest of Mesoamerica's religious practices and values. Human 'sacrifice' was not separate from all the other ritual acts and practices of the Mesoamerican people, including burning incense, dancing, singing, feasting, offering flowers, seeds, precious stones, marine shells, and performing auto-sacrifice. This leads to the problem where some people think that human sacrifice was the only form of religious worship in Mesoamerica! It also makes it easier for nonsense ideas to persist, such as the one that human sacrifice was to obtain flesh for cannibalism, or that wars were fought solely to take prisoners. Despite these ideas being long debunked by experts, people still believe them because they have no real overall understanding of Mesoamerican religion, and just see the sacrifice and draw all their conclusions from that perspective. Meanwhile, it obscures the meaning of the practice among Indigenous people. Among the Aztecs it was called nextlahualli, which translates to debt payment. This refers to the idea that the gods had given humanity and the world gifts such as maize, joy, beauty, and rain, and that they needed to be repaid for this. In return, the gods would keep those giving those gifts to humanity. Second, rituals, including human sacrifice, regenerated the world by restoring it to an earlier, more fertile, state. This concept was described by David Carrasco as 'World-renewing.' There is also the idea of the ixiplta, or god-impersonator. This can refer to an image or representation of a god, but it can also be a human actor. This is the being that is sacrificed during a ritual. The idea is that a person/object is imbued with the power of the god by going through a series of ritual acts that transforms them into a divinity. These acts conceptually align with myths in which the gods enacted creation. However, in the Aztec pantheon, most of these gods ended up sacrificing themselves, and so their ixiptla must also 'die'. The word 'human sacrifice,' with all its western baggage, doesn't really capture any of this complexity. And I've only touched the surface of this complexity. This is the case for the Aztecs, and the Mexica in particular, but as many Mesoamerican peoples shared similar concepts, the Maya likely had similar beliefs.

Of course, Aztec and Maya religious practices were not separate from their political or social realities. 'Victims' were often rivals or enemies who had to be killed ritualistically to 'restore the correct order,' or they were enslaved criminals. And this is where the element of double-standards and hypocrisy come in. All over the world, nations (not just pre-modern one either) have carried out executions of enemies, rivals, dissidents, and undesirables, and these acts are often excused through religion. In Europe this included the execution of 'pagan' peoples after battles, repression of heretics, and religious wars against other faiths. This includes in the Americas, where violence against indigenous people was often justified in religious terms. So, the question is, if everybody does it, why do Mesoamerican nations have their particular form of religious brutality described as 'human sacrifice,' while other groups, say the Catholic Church, does not? In other words, the term 'human sacrifice' has a way of prejudicing the reader/listener against Mesoamerican societies and divorcing their actions from social and historical context, and so a few historians have decided to try and combat the problem by redefining the practice in the historiography.

Sources:

Berdan, Frances F.: - ‘Material Dimensions of Aztec Religion and Ritual’, in Wells, E. Christian, and Davis-Salazar, Karla L. (eds.), Mesoamerican Ritual Economy: Archaeology and Ethnological Perspectives, (Boulder: University Press of Colorado, 2007)

Carrasco, Davíd: - Religions of Mesoamerica: Cosmovision and Ceremonial Centers, (Long Grove: Waveland Press, 1990) - City of Sacrifice: The Aztec Empire and the Role of Violence in Civilisation, (Boston: Beacon Press, 1999)

Kerkhove, Ray: - ‘Dark Religion? Aztec Perspectives on Human Sacrifice’, Sydney Studies in Religion (2008)

Restall, Matthew: - When Montezuma met Cortés: The True Story of the Meeting that Changed History, (New York: Ecco: An imprint of HarperCollins Publishers, 2018)

Sigal, Pete: - The Flower and the Scorpion: Sexuality and Ritual in Early Nahua Culture, (Durham: Duke University Press, 2011)