It does not mean there is an error in thinkingSpeaking in such absolutes (no one would even think...) typically shows an error in reasoning and is in fact a fallacious form of argument.
Judas walked with jesus for three years and could probably do the same.I sat with a man once who had been very active in ministry in his church for years and who could answer virtually any question I could ask him about Christ, about faith, etc. and who said he had believed, explained to me what he had believed, but no longer did and had recently walked away. He was very open to discussion but was resolute in his decision.
I don't and cannot know what happened with him after that, but nor can I say no one would even think... because I see in our Text that they can and I've experienced the above face-to-face.
We know for a fact Judas never had faith..
so nice try