From what I can gather the crack down has nothing to do with NSFW stuff involving violence, drugs, alcohol and the like. But the depictions of gruesome deaths (gore in general), significant physical abuse (Twilight fandom point your torches at 50 Shades of Gray plzkthx), rape and explicit sexual content that is erotica being limited seem to be a goal. Not the only goal, likely, but a primary goal. On the one hand, surfing this kind of site, I want to be able to be stonewalled by hitting a NSFW piece, but that same block page should say "Hey dearie, this page was blocked because the Creator checked these boxes! Do you want to continue?" and then it has a list of boxes the creator put in, akin to what Ao3 has.
That said, Patreoners are being hit because the site became the fast and furious place to get erotica nudes of non-professionals (sexy cosplay is a top one that comes to mind, namely that group Cosplay Deviants). Is there something bad with modeling underwear? No. When it's done in a photograph to evoke sexual arousal, mmmmm if someone has consented to seeing it (by paying for it, entering said bar, or what have you) then sure. But when that money has to then cross the threshold of PayPal, a company who does not want to be in the business of blatant sex like that, supposedly, then banhammers come down.
Remember that sadly these companies have public images to uphold and if it becomes commonplace that their company is seen as the "Go To to get nudes of xyz" like Patreon did, then you will see reprocussions. Tumblr followed suit because it did have that, even if you didn't go there, and it commonly had sex bots and the like, and cosplayers and artists would and do post teasers to their NSFW content on their Patreon. Again putting Patreon as the "Go To to get erotica".
As for Tapas reacting like this without a statement, not surprising honestly. They likely don't have the AI or coding hardware to sift through this kind of information without some employees double checking. And what about people who do not censor their work, but censor just a few chapters/pages, or censor nothing at all and yet what's within is one of the 'unsuitable' things I listed above? Hammers will happen. Patreon likely isn't the start of all of this, but it's affiliation with payments with PayPal, just like Ko-Fi, you are bound to see similarities. If it's not already happening, dA's system is also bound to be hit by something if they intend to keep PayPal as a pay option up for Points (which can be converted to real money to pay the artist who's received them).
That sad thing is this isn't primarily aimed at artists. It's just going to "swing hard and wide at first" and then become more specialized and acute as the need happens. There's a reason the "yaoi/yuri wood flat bats" were banned en masse from anime cons a decade ago and remain banned.