It's their choice, if they only want to participate bounty, they're not required to have minimum rank to join.

I mean, those reasons aren't only happen in this forum. EVERYTHING must need time and dedication if you want to learn something, it's just a common sense. How is possible someone can send Bitcoin when they don't have any coin? obviously learn how to buy it.

There's no relation between rules and rank up, all you need is never do plagiarism.

Ranking up isn't a must, as long as you're good person and not scam or scam, you're good.