Earlier quoted context omitted.
It's an bad question to ask outside the context of a relationship. It's like asking a very personal question of someone before even meeting them for a first date. 'Who the LP's are' is basically none of your business unless you are entering into some kind of relationship, even then - it may be out of bounds. Of course you have the right to not take money even in that case, but that's a different thing then knowing wh…
You still haven't explained why it is poor form, besides saying "it's a bad question to ask". I see many words but no explanation.
It would be like some random person on the internet sending you an email, asking about specific details on your cap table.