I suppose this highlights risks from a general increase in credibility-giving by close temporal association with other new ideas you're giving credibility to?

Yes, this.

Usually this risk is low, but here it was actually quite high. This particular instance was an Ugly example, because the category - ideas with close temporal association - was false. But there were many scary examples based on good categories. The most outlandish was meditation. Remember that other people's brains are part of evidence, now witness quite a few people who have just spent the last few days on activities that convinced you they are pretty decent (compared to baseline, damn good) at doing their research, discarding bullshit, not strongly espousing ideas they don't strongly hold, examining the ideas they do hold, etc. etc... witness them say with a straight face that meditation, which you (I) assumed was a crock of mystic religion that just took a different turn than the Western religions you're familiar with... witness them say that meditation is super-useful. Then watch your brain say "Bull! Wait, they're good at things. Maybe not bull? Hey, argument from authority, bull after all! Wait, argument from authority is evidence... :S I... have to take this seriously..."

IFS, NVC, nootropics? Guess I have to take them seriously too.

(I exaggerate slightly, but my feelings were stronger than I think they should have been, so that story is in line with how I felt, if not precisely what my beliefs were)