Axel too self-hating (spoiler)

His attitude is really irritating. He refuses to have sex with other Germans (without giving any reasons). He expresses amusement when Eyal tells his story about how he harrassed people during a visit in Germany. He has no problem bringing a foreign secret agent to his parent's home. His mother could figure out who Eyal was, so I assume that Axel could as well. At the end, he single-handedly murders his own grandfather because he feels entitled to bring him to justice. Granted, he was probably a war-criminal who arguably deserved to die, but come on, it's still his granddad and who is Axel to execute him.
I mean, he is such a nice lighthearted guy and he can put up with Eyal's displayal of blatant racism, yet he seems to hate and despise his own country somehow. It certainly makes his character look like a hypocrite and not very likeable. Or at least, there seems to be an untold story about his mindset.