I noticed that when you are all-in from QQ or JJ from the early position, in most cases you will play against KK and AA.
Since EP puts you at the worst possible advantage, your raise lets the other players know that you are strong. So, what
hands are another player going to play against a strong hand ?
VERY strong hands ! What does your EP raising range look like ? Do you also have some lower pairs and higher suited connectors in your range ? If you only raise in EP with your strongest hands, then you are giving away too much information. I think this is why JJ/QQ are considered difficult hands to play.