[erroneousfunk]

"You're too white to be a Brazilian" and "you're too tall to be a jockey," while in poor taste to say, do have explanations behind them. Brazilians are usually descended from black African slaves, native South Americans, Southern Europeans, etc. Many people forget about German and other East/North European ancestries. Jockeys are usually very small, so the horse can carry less weight and run faster.

"You're too attractive to be an engineer" makes no sense at all. It baffles me that you'd try to compare the statements.