There is a difference. For the olympics it is indeed a bit childish (though the olympics cost a ton of money so that may have been a factor). For the nobel prize, there is nothing he did to deserve it imo.
Granted, he did no start a war and he has extended diplomatic talks to countries like Iran. And that is very much a positive thing. Bu it is nothing that other countries don't do already. It's like being awarded for not beating your wife. You're supposed to not beat your wife. You don't get credit for it.