I wonder what triggered this - legislation? Their payment processor? The ad network they get their revenue from? In my experience, this kind of change happens much more often for money reasons than for moral reasons. I think Tumblr's TOS change happened because their credit card processor became uncomfortable at them being essentially "in the porn business" - and indeed, seeing how much smaller Tumblr's business was…
https://www.salon.com/2019/08/16/did-banning-porn-make-tumbl...
> Porn was banned from Tumblr soon after the social network was removed from Apple’s App Store. Child pornography was found on the site, one consequence of the site’s relaxed content moderation approach. Instead of banning specific sites with child pornography, all not-safe-for-work content was banned.