Not to discourage further answers (especially from people more familiar with the actual book in question), but u/J-Force addressed this question about that very statement here: https://www.reddit.com/r/AskHistorians/comments/p5niz5/how_accurate_is_tom_hollands_claim_in_his_book/

One of the listed sources is conveniently on jstor (which you can read with a free account!): https://www.jstor.org/stable/3653973

u/Tiako also has an answer here, https://www.reddit.com/r/AskHistorians/comments/odl72c/how_do_academics_feel_about_tom_holland_and_his/

And finally, J-Force is back again to discuss Tom Holland in general - https://www.reddit.com/r/AskHistorians/comments/ig9vtw/what_makes_tom_holland_unreliable_as_a_historian/

on a similar topic, but on the other side of the coin...
how reliable is Catherine Nixey's The Darkening Age - The Christian destruction of the Classical World ?

reading the first chapters, she really paints a bad picture on early christians, them being more destructive to the classical culture than the gothic migrants that invaded the Roman Empire.