Bulma just rolls her eyes at Vegeta's reaction, of course he would laugh at other people being beaten down, that's something that apparently will never change in him, and she's glad for it. It's still quite rude and heartless though.

"Certainly, with the heritage your father has left to you through genes I can't see you using a weapon regularly. Saiyans just aren't made to manipulate weapons, though being a half-saiyan and with how my genes have influenced in you I'm sure you could use one;" if that sounds as if she's subtly implying that saiyans don't have enough brains to use weapons that's... Probably because she is doing exactly that. Of course, Bulla is different, she has got enough of her mother's brains to not fall in that sack.