On other browsers too but that’s hacky.

I don't really think it's hacky. For many years I would run 2 browsers side by side. Firefox for personal and Chrome for Business.

It makes a nice separation and you don't need to worry about whether some tool you like to use has fancy multiple account tech. If the big guys like Google and Facebook can't get it right, I think it's unreasonable to expect smaller players to do better.

You never need to think about who your are logged in as or who you are posting as.

You're using a feature of a program on your computer to circumvent account access decisions on someone else's server. This the definition of "hacky."