It's not really a new issue, Mastercard and Co have practiced this kind of gatekeeping for a while.
Why does that matter, though, can you explain?
The fact is, virtually every "bad thing" exists "for a while" before it surfaces and becomes noticed by a larger group of people. I can't actually think of any real exceptions. As far as I can tell, moaning about that serves no purpose unless people were broadly aware of it and just disregarding it - which is rarely the case in my experience.
I guess many folks who now bemoan the banning of LGBT material had no issue with the loss of Hentai. And many folks who now say that the loss of LGBT stuff doesn't affect them would certainly care if "satanic" books like RPGs are no longer available.
I don't think that's half as true as you seem to be claiming it is. I think it's more likely they were simply unaware or didn't believe change was possible. My experience is that people are not generally just ignoring these issues, but that they're sufficiently obscure that they're not aware of them. Not helping matters is the press, particularly, and I hate to use this term, but it is relevant, the "mainstream media", who fairly consistently misrepresent this sort of thing as being "just getting rid of stuff that was illegal anyway", if they report on it at all, and most often they just bury it.
This isn't really a "First they came for X and I ignored it" kind of situation for most people. This is a "First they came for X, then Y, then Z and I had literally no idea about any of that until they came for AA"-type situation.
It's also very helpful here that the scumbag organisation who pushed Visa and Mastercard into this decided to crow about it very publicly*, so instead of this being some nebulous decision which most people (including those impacted by previous moves) assumed was corporate de-risking driven by the legal departments of the companies involved (something we are now realizing it never was), we know this was an organised campaign by a fairly small number of weirdo extremists with an agenda distinctly out-of-line with most people. That the cause is that, not "the legal department" gives people the confidence that they can fight back, that they too can bully the shmendricks at Visa and Mastercard. Because there are a lot more people pissed off by this than the tiny number of Aussie weirdoes who caused it.
* = Which speaks to their confidence and their certainty that the media would be on their side - a justified certainty given how much of the media has been very eager to lie and intentionally misrepresent stuff about LGBTQ+ people, especially trans people, in the last few years, and promote and indulge columnists who, were saying the same sort of demented things about say, Black people, or white middle/upper-class cis gay men, would have been immediately fired on the spot)
