Someone gives you a link, or you find it in search
You click on the link, because that’s what you do with links
It takes you to what you are looking for, but it says you have to log in to comment or vote
You log in so you can comment or vote
The UX for interacting with off-instance subs is abysmal. What is even worse is that as far as I can tell, there is no way to link a post or comment that is instance relative / instance independent.