I would consider pirates more of a support class. They are there to annoy the shit out of people dueling and to damage people so teammates can finish them off. The reload time on their ranged weapons takes some time so they’ll need a teammate to back them up. I completely understand the hate for Pirates, because their design is about pissing people off while the Pirates teammates easily kill you.
Luckily, I have not meet a really good pirate, so I can’t speak for everyone but I don’t feel that pirates are such a big threat. If you can manage to get past his teammates and focus on the pirate, he is forced to run but because of his low movement speed, he’ll get stabbed in the back.