Boomers aren't even online all that much, since they're too busy watching CNN or TV Land or Turner Classic Movies, or doing their crossword puzzles, or whatever, so where would you even encounter them, to be able to say that?
I don't think they really misunderstand. The debates going on today are the same debates that always went on, e.g. back in the 70s, when they were trying to pass an Equal Rights Amendment, or in the 90s, when there was date rape furor, about how everything is going to be fucked up if we give women all these rights and take away men's rights and whatnot.
Also, people were giving boomers a hard time even when they were teenagers and college students, telling them to quit with all this degenerate behavior, and they didn't listen.
So it's not really about a cultural divide all that much between boomers and Gen Z. It's just that boomers have never been willing to let anyone talk them out of being feminist, regardless of whether it's their parent's generation, or their kids' generation, or more conservative members of their own generation, etc.