One way to look at it is that "elsewhere" is a protest pen, just like in the physical world where there is a plan to host this year's G7 protests in Plymouth, 76 miles away from the G7 venue [1].

[1] https://www.plymouthherald.co.uk/news/plymouth-news/mp-fears...

World is big. As long as there's a browser without built-in censorship (malicious websites filter, kek...) and world-wide Internet, that's not an issue. Parler can always host in Russian data center, for example, who could care less about US politics shenaningas, just like Russian dissidents are hosted in EU data centers.

World is big, but eg. mobile ecosystem is basically google and apple, and both banned the parler app.

You don't need app for something like Parler app. It might be more convenient (and even that's questionable, Reddit app is terrible compared to website), but it's not necessary.