pps: roflmao at not seeing the word LIMIT.
In the JJ hand, if I raise, everybody calls getting between 7:1 and 11:1. Then if I flop an overpair, I can't even protect my hand from draws with a checkraise. 4 opponents is the worst equity situation postflop for JJ (in LHE).
As for the J4s, hand, folding makes sense, I agree. raising is spewy since again, no decent player folds preflop once they've put money in.