I always understood the intention to be that you can't join the pirates if you are a nobody.
If you are somewhat famous, they might be interested in having you join.
Perhaps it should check your reputation instead though, just like the pirate stores and shipyards do.
In any case, I think the idea was that you can't join the pirates straight away early in the game; you have to put some effort into being allowed to join.
On the one hand, that is quite fun. On the other hand, there is not much of an advantage to joining them.
You just get more enemies.
If you are somewhat famous, they might be interested in having you join.
Perhaps it should check your reputation instead though, just like the pirate stores and shipyards do.
In any case, I think the idea was that you can't join the pirates straight away early in the game; you have to put some effort into being allowed to join.
On the one hand, that is quite fun. On the other hand, there is not much of an advantage to joining them.
You just get more enemies.