Can confirm that feminism is unpopular among the young male demographic here. Here's a fairly decent explanation of this situation that I picked off the Korea subreddit:

Now on Koreans and feminism: it's not really appealing to young Korean males when they're told they're privileged, due to certain societal norms and pressures. That's probably the case for most places but I'm not sure many have the strict railroaded path to adulthood that's present here.

Kid comes out of high school and if he's lucky he's conscripted immediately or face prison. He spends two years divorced from education getting obedience beaten into him and when he gets back, he needs to re-study to the point that he was at high school level, and then apply for college all over again. So when he joins society as an adult, his first job will be 25 years old. If unlucky, he will already be in college and get swiped before finals - he will have to wait for the start of the academic year and retake the same year and be 27 when he starts his first job.

His high school female friend got out of college at 23 and started. By 3 years, she will already be an assistant manager or a section manager or achieve it 2~4 years before him, forever his superior that he must bow to. She will have a higher income than him by default. The only difference between them is their gender/sex.

Now, he is a male. He is expected by society to provide the bulk of the funds required to secure a house and possibly a car. He is considered ineligible, a loser, by the middle-class if he doesn't have a decent lump sum of money so he will forego many expenses. Meanwhile, it is a very acceptable lifestyle for a young woman in her 20's to spend most of her income traveling and spending. She is not and will not be expected to provide.

Even with these inherent handicaps, men are still expected to earn more than women when considering each other for dating or marriage. There are no slurs for women who don't earn much income but there are plenty of words for men who do not, which you will find used predominantly by women than men.

A societal problem that feminism will address, clearly, since feminism in most of the world is about breaking this gender roles and bringing gender equality? Unfortunately not. Feminism here focuses on dismantling the institutions which are genuinely unfair to women but it usually stops there - the equality espoused can therefore be seen by many young Korean males to be a front. Sometimes the institutions set up are genuinely baffling for a western audience - reserved parking spaces for women that are placed near disabled spots, performative leniency provided by the conglomerate companies exclusively to women, etc.

Physical and dirty labor that needs being done in the office? A male newbie does that - telling a female one to do that is frowned upon. Cleaning duties? An old dinosaur might assign a female but no, the modern superior is not sexist therefore to remove all shadow of a doubt, the duties will be assigned to the male. Petty, small things that aren't on par with the existential problems of being expected to be the provider despite handicaps, but still things that get brought up as 'evidence' of 'female preferential treatment' - on the macro and micro scales, young Korean males can have things to point to and focus on exclusively without seeing the other side of the argument.

Of course on a macro and micro scale for women, the genuine problems of sexual crimes, violent crimes, spousal abuse, childbirth being an end to many careers and their own societal pressures exist. These are injustices that need correcting but somehow the political capital gets used on those other petty, small things that I mentioned earlier. And people don't focus on what they have - they focus on what they don't have, so the issues that need addressing aren't at the forefront of young males (they do acknowledge it if you nudge them, but it's not the first thing they seem to think of). Getting these two sides to see eye-to-eye has been so far impossible for the most part, to the point that the middle ground has given up and the only sides that are willing to keep talking, are the screaming extremists from both sides of the divide.

The reforms being pushed for by Korean feminists that get heard on the ground don't always tackle the genuine issues of crimes and societal pressures. The ones quietly pushing for reforms that make meaningful changes don't necessarily get heard. A common refrain that results due to that is that the perception of a "feminist" in Korea is "wants all the privileges without the responsibilities". That phrase alone is a lot to unpack but I've written a lot already and I'm not an expert on any of this.