Funny you should mention that. 'Kill All Men' slogan originated from the S.C.U.M. manifesto written by Valerie Solanas: A feminist who tried to kill Andy Warhol. To your point though, women aren't typically out on shooting sprees. Does that mean women can't do any harm to men? Does it have to be murder to matter?
People may claim that ironic misandry isn't harmful, I disagree. Given how divided we are, particularly between genders, I can't see how it's helping. I think ironic misandry can have a normalizing effect on actual misandry. I've seen articles that basically say that misandry is not that bad. It's "ok". Because of systems of oppression, some say it's actually warranted. (Misandry is just a response to misogyny....and such)
Actual misandry is associated suffering of males being mocked, minimised, dismissed, encouraged and even celebrated. It's one of the reasons men lack the support systems to deal with issues like suicide, domestic abuse and homelessness. I've seen women online claim "they have all the rights" as a way of dismissing these issues. Maybe they are just responding to how the topic is brought up, but their message is still dismissive.
I agree that majority of women care about issues that affect men. At least until acknowledging those issues conflicts with a Feminist narrative. Domestic abuse as a gendered or not gendered issue controversy is a perfect example. As long as we insist that it's a gendered issue, men will always be the considered the abuser and women will always be the considered the victim and abused men will continue to suffer in silence.