Question

Being a poor sport only applies to those teams that lose a competition

Answer 1

False.

The winning team can brag about being the winners, and the others being the losers. The losing team can whine/complain about being the losers instead of congratulating the winners and accepting their defeat.

Answer 2

is this a true or false?

if so, I thinks it's false. you can be a poor sport even if you win by bragging and stuff, imo