No. You have a right to "play around". I once underpromoted pawns to Knights to "send a message" that my opponent should have resigned many moves before I started doing that. Just be careful that you do not stalemate. I usually "go for the throat" and try to end the game as efficiently as possible.
Is it unpolite to make three queens?


I get more than three queens all the time.i once got 7 queens. If your opponent is not resigning because he is low rated or wants to play till mate you can torture him however you want.

If you're playing people where by you can promote umpteen queen's then you really should look for a better challenge
It's a bit rude (above beginner level, beginners can play on to hope for a stalemate) but it's not your fault. Your opponent shows that he wants the humiliation by not resigning.