It's not about being infallible or invincible but not even acknowledge that a) Jean noticed Logan was under the influence of another telepath and b) not doing anything to try prevent her own or her team-mates deaths is just stupid, I'm sorry.There are ways around this , she could at least try and explain that PG isn't a telepath exactly but controls the soul or something ,but it was really bizzare to avoid the circumstances of the incident with her status and later we get the Nightmare smackdown.I just don't buy it, we need consistency.