Tumblr was a safe haven for a lot of LGBTQ niches, for most of them it was the only place they could go that wasn't fetishized to hell. They created a safe place for those. For some of them there were blogs that were NSFW technically but they were about sex ed.

Banning NSFW wasn't removing dudes shoving porn spam, it was about removing all of those safe havens. With those gone for some it was no longer what they need d and for the rest it proves that the trust had been lost.

People like porn and it's most of the activity on the internet. Taking porn away means you lose a substantial portion of your activity, including people who used your site for both sfw and nsfw content and shit snowballs as advertisers and other members see activity die.

I'm guessing. I didn't watch either.

very abbreviated tl;dw: Adult content mattered because people could express and explore their sexual identity, not only LGBTQ+ people but everyone. After that disappeared, the users didn't want to interact with a corporate site which is trying to exploit them. It went from indie project to Verizon/Oath daughter company.