And so what? I haven't watched his talk, but by the summary of it it seems like his talk was consistent with his previous statements. Did Snowden destroy his credibility when he "shared the stage" with the scammer in this video?

https://www.youtube.com/watch?v=Hv3UC4lz3oQ

It seems to me that the only thing that matters in most of the "crypto community" is that you are contributing to the price going up. When Musk took away the ability to pay with bitcoins the hate for him in every crypto subreddit went through the roof. No one gave a shit about his reasoning. I have a feeling the hate for Taleb is the same, he is not contributing to the price of bitcoin going up, so he is hated by those who have invested in crypto.

Could you be more specific on how he has "destroyed his credibility", is it simply because he is negative towards crypto?

Attacking the person without touching on what they are saying is called an "Ad hominem" and is a common logical fallacy:

https://en.wikipedia.org/wiki/Ad_hominem

That said, Bitcoin is almost purely based consensus reality for most of its existence. It is worth something because others feel it is worth something.