The US Federal government no longer protects reproductive freedoms like they did a few years ago, so some states have been cracking down on procedures like abortion and using data from places like Facebook to gather evidence. Depending on the state, having this data might lead to legal headache, but I’m not sure how likely that is.
If you read any of his memoirs or interviews, you’d know that his intended destination was Ecuador, and he couldn’t fly out of Russia due to his passport being revoked. He lived in the Russian airport until he was granted asylum, so it’s not like he had much choice.
I didn’t see any sources that went against those claims except from WikiLeaks, so I don’t see much of a reason to discredit them.
Then don’t use Meta products?
If the reason why social media is free to use is because it’s subsidized or paid for by personalized ads, and they now can’t use personalized ads, I really don’t see the problem in putting it behind a paywall. Social media isn’t a public service. It’s a business. We aren’t entitled to Instagram’s free unlimited video hosting in the same way that we aren’t entitled to free movies from Netflix or free electricity from a private utility company.
Defcon is a useful resource for networking and learning. It being run by and for good guys doesn’t mean bad guys don’t find the event useful. The vague risk of “getting caught” is probably worth taking, regardless of whether that risk is tangible, especially if they follow proper security practices.