Tim didn't fess-up about "having Knowledge" because he knew that would mean there'd be no talk and he was really interested in talking to him and asking him about what it was like for him on-stage in the 70s. He did confess afterwards to the minions.
Tim is used to being polite to people he has public talks with as you said, a nice guy.
Premies are not outraged because they "know" he is the Lord but that his safety is more important than the truth and they probably also believe it was their deluded thinking.
Its called cognitive dissonance but there's no actual dissonance because they're above the mind, they're in their heart.
