Though others have pointed out alternative interpretations of the poll (such as merely disagreeing with the label, not the ideals, of feminism), I am going to voice the minority opinion here: the straightforward interpretation may be right. In fact, I unfortunately find it completely plausible. Millennials, after all, went through ten formative years of #MeToo and BLM, the biggest protests for equality in a century. The younger generation aren’t going through a cultural revolution anywhere near that scale. Things have quieted down, and sentiment may have regressed to the mean.
I also think people may be underestimating how powerful rightwing bro media has become, with radical figures becoming mainstream like Jordan Peterson and Joe Rogan, etc. I don’t see many countervailing feminist voices with as much reach, especially those targeting impressionable boys. I’m not sure about any of this, and I know some may not like to hear the alarm, but I think we need to be realistic about the possibility.