Disengaging from random arguments isn't the problem; the problem is living in a world where nearly every opinion you see more or less aligns with your own views, to the point where we've been conditioned to see dissenting opinions as being hostile to us to the point where we instinctively reach for the unfollow/block/mute button when we see them.

Why does that mean people shouldn’t be able to pick and choose who the talk to on social media?

It's not about picking and choosing who you engage with, it's about filtering broad-stroke opinions you disagree with out of your life entirely, such that when one sees any trace of an opinion that runs contrary to their own internal narrative, they reach for the block/unfollow button, instead of engaging to find mutual truth, or even just ignoring it and scrolling past it. Just a few years ago, when someone saw an opinion online that they disagreed with, it didn't fill them with the urge to remove that opinion and any chance of seeing similar opinions from their worldview, but that's how we've been conditioned due to social media being used increasingly politically.

Again it is unclear to me how you have arrived at a duty people apparently have to carefully consider noxious arguments from strangers.

You're still not understanding what I'm saying. There's a huge difference between ignoring/not engaging someone saying something you don't agree with, and filtering them out of your reality via mute/unfollow.

And that difference would be...

Are you really arguing that you have a right to pick a person at random and coerce them into at least seeing what you have to say before making a decision to ignore you?