Indeed, many feminists are campaigning for men's rights in areas like domestic violence, custody cases, etc.
Those aren't feminists. Well they are, but not the kind of "feminists" that someone means when they use the word online. We're really having a language issue here as we are using the same term for two almost opposite groups, and so are those groups themselves. The feminism that reddit hates is exclusively 4th wave feminism (and sometimes 3rd wave) also known as "tumblr feminism". The feminists you're talking about are more feminists in the classic sense, so 1st/2nd wave, choice feminism, etc... all the kinds of feminism that 4th wave feminists consider just as evil as MRAs. Classical feminists that genuinely care about issues of both genders and don't see themselves as perpetual victims of an imaginary patriarchy are absolutely awesome, and most anti-4th-wave people I've talked to would agree on this (anecdotal, I know).
Do you realise I could replace the word "feminism" with "anti-feminism" or whatever you would call your stance? I dunno that it's fear but whatever sentiments and feelings you and your like have about feminism, they certainly come across as hysterical and baseless. And as I mentioned, your stance does not really encourage open discussion.
As someone else has pointed out, the post you responded to was indeed a bit hostile, but not hostile enough to completely shut down reasonable discussion - as evidenced by the fact that you started reasonable discussion in response to it.
The "replace feminism with anti-feminism" idea is completely and demonstrably wrong:
baseless fear
This is the closest to applying to anti-feminism, however the fears of anti-feminists are not baseless as 4th wave feminism is gaining legitimate traction IRL and therefore could cause real damage outside of just tumblr. However a lot of anti-feminist posty is just as sensationalist as feminist posting, as anti-feminists like to be outraged by feminism. I see this as a way of venting their frustration about 4th wave feminism, and therefore consider it healthy.
based on outright lies.
Can you provide an example? I can't think of any anti-feminist talking points that are outright lies. I've obviously run into some that were based on slight misinformation or were outdated/out of context in the form they were presented, but there's a huge gap between that and outright lies.
silences free speech, open discussion and the slightest hint of dissent
This is the most demonstrably wrong across the board. If you compare major anti-feminist youtubers (which, based on the support they are receiving from the anti-feminist community, are the closest thing the movement has to public figures) with major feminist youtubers you will see that anti-feminist youtuber's virtually never disable their comments even when they're filled with mostly dissent, whereas a vast amount of prominent feminists on YT and other parts of the internet disturbingly often resort to blocking people (there's pre-programmed "block lists" they use, google it) and disabling their comments, then crying about "harassment". While I am of the opinion that it is within anyone's right to disable their comments or block anyone they wish and I don't hold that against them, you definitely cannot tell me that anti-feminists "silence free speech/dissent" either as much as feminists do if major internet feminists seem to silence dissent at every opportunity whereas anti-feminists actively avoid doing so at every turn.
Good examples of YT personalities that would consider themselves to be "anti-feminists" at least regarding 4th wave feminism: Sargon of Akkad, Thunderf00t, The Amazing Atheist, Mr Repzion, Armored Skeptic, anyone who can think of more feel free to add to this list. These people don't agree on every issue of course, which further shows that differing opinions are very much accepted amongst anti-feminism.
That is all.