People who are pissed are angry because it looks and sounds like bait and switch.
Usually the slippery slope argument is a fallacy, but if a company says "our standard is and always will be 1" and then comes out later and says "our standard is 2," it's hard to believe.
There's free speech and free speech. Reddit can advocate that it's in favor of free speech while simultaneously banning the sharing of child pornography, bestiality, death threats, and revenge porn. So does Twitter. So does Facebook. So does Google.
If there's an argument to be had here, it's an argument about where the line should be drawn between "acceptable" and "never acceptable." Reddit's in favor of moving the line to acquire more interest from the outside world---a world that has generally (read: "in the markets Reddit's funders care about") categorized revenge porn and overt racism to be never acceptable. The existence of the line itself is not in question, and entities that have such a line are not in general accused by reasonable people of standing against free speech.
So either you can draw this distinction by saying "these topics are legal/illegal in most countries", at which point IMO you're back at making a subjective call.
OR, you could say they are operating from within the legal framework of the country from where they run their main business. Which is the USA. I'm not even sure whether this can still be said about Google or Facebook, given their Irish/Dutch tax haven constructions (I'm unaware if Reddit and Twitter do this too).
But then you have to claim the USA legally has the most free-est speech in the world, the superset of all things considered freedom of speech globally (admittedly, the US has less restrictions on free speech than the Netherlands, where I live), which I don't think is the case actually (though the US' few particular restrictions are quite sensible IMO).
I'm quite happy with the fact that we don't (really) have a global encompassing legal framework to define what is and what is not free speech. Even if that means some (nation) states will get it "wrong", it provides us with perspective, hopefully both with examples to avoid, and others to look up to.
This makes Freedom of Speech, in the context where it does not pertain to legality within a particular (nation) state, but in the context of transnational businesses like Reddit/FB/G/Twitter/etc, more an ethical consideration rather than a legal one.
And I prefer it that way, laws are just The Rules, you need to follow to (say) operate a business (hopefully the Rules work for the greater good of that particular society). But Ethics is the stuff that makes your decisions Right or Wrong.
And that is what I'm going to judge a company by, if they operate where I live, but are bound by legal rules from elsewhere.
Revenge porn specifically?
(Follow the train of thought to its conclusion).
Most of Reddit's users aren't going to find their subreddits of choice interfered with.
And honestly, the people who are going to get smacked by this are well capable of forming social connections that transcend Reddit, so they haven't lost all of their investment. But investment of time doesn't in itself guarantee a refund---never does, shouldn't be expected to without a contract in place.
Well, what's that time worth? If they can find a site that will pay them all for that time investment, then maybe we could start to attach a value to it.