[This is all very uncomfortable, and it's not just because of the mention of mass genocide. If Kitty was in his universe, she'd likely be as against cylons (also genocidal, also the murderers of basically everyone's parents) as she is against this Apocalypse character. She certainly wouldn't have much sympathy for people who collaborated with the cylons, however good their intentions. Maybe she would've been right there with the other people who wanted to throw Gaeta out of an airlock.
Or maybe he's wrong. Regardless, he's visibly uneasy even if he won't verbally acknowledge as much.]
There must be a reason for other mutants to side with Apocalypse. They can't be in it for the murder.