People whose existences are deeply politicized (and they do indeed exist) are not often excited to have political conversations with people who say things like "'existence is political' thing is just a bullshit phrase."
I'm not trying to be a dick, but it took me a long time to realize that there were conversations I was not being made a part of because I was not receptive to, or dismissive of, those conversations.
It's of course not universally true that's the case for everyone, but I think it's worth thinking about. If your attitude is dismissive of someone's lived experience, it's not likely that they're going to go out of their way to include you in conversations about it; on the contrary, I'd expect them to explicitly exclude you in order to protect themselves.
This is a tactic that needs to be called out more often.
It is a bullshit phrase though. They don't want to bring it up because any skepticism is viewed as a direct attack on their ideology, and their ideology is the core of their existence/identity, so, calling out the illogic of their ideology is a political attack on their existence.
They want to TELL you, they don't want a discussion.