Were we scammed by the mainstreaming of non-monogamy?

I feel like since the option to be non-monogamous has become more mainstream, and this especially in recent years with the option for example of selecting « non-monogamous » on dating apps, men have sort of exploited this presumably liberal loophole to just expect us to be « open » and accepting of them sleeping with other people. I feel like a huge proportion of them openly now admit they want to sleep with other people than their partner and we’re somehow made to feel close-minded when we have a profound objection to that as if it’s entirely morally neutral, when in reality, sorry, but these guys are not free thinkers… they’re just sex pests.