I think he is just a giant nerd who's one of the most famous human beings by accident (he cleary felt more and more uncomfortable about this side of fame with age) but he's dealing with in his own silly way and just doing whatever he wants, giving a single f*** what others are thinking about him. To me that's one of the most admirable features of him... to have the self-confidence to show the world his inner, imperfect geek. That's part of his charme and success and why so many people admire (or hate/envy) him I would say. Because he doesn't have to be great to be great.
Not showing affection in front of a damn razzi lense is one of the most normal things to me btw. For me it's not Leo acting ridiculous it's us who propably never felt this constantly amount lack of privacy, but expecting that he reveals even more of himself and showing his most private feelings the world (and it's not like he never would).