Well, frankly, I'm not sure the two are mutually exclusive. However, there is some validity to this statement in that the Spanish conquests of the Inca and Aztec empires were less like conquests and more like coups d'état. Pizarro happened upon the Inca empire during a civil war. One of the two combatants, Atahualpa, had just defeated his rival when he met with Pizarro. Pizarro used the excuse of a diplomatic meeting to grab the emperor and hold him hostage. The rest of Atahualpa's retinue were unarmed, and Pizarro's men massacred them.
Since the Inca empire had been in civil war, the other side (which had backed Atahualpa's half-brother Huascar for the throne) used the death of the emperor as an opportunity to reassert their power. Pizarro and the other conquistadors were able to exploit this situation by playing the factions in the civil war against each other. Their position in the early days of the conquest was very tenuous - they were able to maintain control only through the cooperation of native elites. Those elites, in turn, were using the conquistadors as allies to gain an advantage against their rivals. To make things even more confusing, the conquistadors then turned against each other.
The conquistadors at this point were primarily interested in enriching themselves, and spent lots of time plundering temples and palaces for treasure. Since they weren't particularly keen on sharing, it didn't take long before they began fighting among each other. Almagro, one of Pizarro's lieutenants, had been denied a share of loot and turned against Pizarro and killed him. This was just one of several such conflicts, as different conquistadors began trying to eliminate each other in order to increase their own personal power within the crumbling Inca empire. The native nobility were involved in these wars as well, for much the same reasons. To make matters more complicated, the Spanish put a puppet ruler named Manco Inca on the throne. He cooperated at first, but then rebelled against the Spanish and was defeated. The remnants of his rebellion established a government-in-exile that wouldn't be fully quashed until 1572.
The rapidly changing political situation that followed the conquest is extremely complicated. You would need a whole book to actually understand it. But to give you the short of it, the conquest and subsequent wars of the early colonial period could really be seen as a continuation of the same civil war that had been raging in the empire since before the Spanish arrived. The war began with the dynastic civil war between Huascar and Atahualpa. Atahualpa eliminated Huascar, then Pizarro eliminated Atahualpa, then Almagro eliminated Pizarro, and so on. The Inca empire essentially remained in a state of civil war from the early 16th century, through the conquest, and well into the colonial period, when it was eventually subsumed into the Spanish empire as the Viceroyalty of Peru. The Spanish inserted themselves into an existing conflict and then continued it.
Throughout this entire conflict, the position of the Spanish was entirely dependent on support by native nobility, who were in turn supporting the Spanish to advance their own interests. The actual replacement of native nobility with a European bureaucracy wouldn't happen until much later, and the changes would be phased in slowly. In 1542, the Spanish attempted to implement a series of laws that limited the power of both the conquistadors and the native nobility in the hopes of preventing further conflict. It didn't go well; Gonzalo Pizarro (one of the other Pizarros) rebelled. He took an Inca/Spanish army and marched on Lima, where he promptly killed the viceroy. It wasn't really until Francisco Toledo took over as viceroy in 1572 that the native Inca power structures were thoroughly dismantled and a European colonial government was put in place.
So in a sense, your statement was true. Pizarro himself didn't really conquer the Inca. He eliminated the emperor and placed himself and the other conquistadors in positions of power. However, he never really had complete control over it, and he seemed more interested in enriching himself than anything else. The actual conquest - as in fully subduing the empire and replacing it's government with a colonial one - would take decades, and Pizarro would not live to see the end of it.
Here's a source that I would recommend if you would like a more detailed run down of the story: