I'm not free to ignore their externalities, though, am I? If my next door neighbor burns motor oil to stay warm in his backyard while promising that he'll switch to something better in six months, "just choose to not live next to him" is not a plausible argument!
The difference, in my mind, is that you are suffering under your neighbour's actions directly and the person on the other side of the argument can do something about it.
Arguments about when/if Ethereum will switch to PoS are different, because neither you are I can do anything about it either way; it comes an argument merely about predicting the future.
If you are talking with your elected presentative who wants to vote against a PoW ban who is holding out for a switch, then that is a different story.
