some future government that decided to go after, say, LGBT people
That's pretty hypothetical. Sure it's possible... but porn companies having the data is almost guaranteed to be bad news.
Some porn companies will sell the data to the highest bidder. And one of those bidders is going to be organise crime networks that will send an email threatening to share your viewing habits with your kids or your grandma - $1,000 and they'll delete the data - they promise. And then they'll be back six months later asking for $100k.
And the ones that won't sell it? They'll probably be targeted and compromised, with the same eventual outcome.