#InfinityWar was a mess of a movie. It had holes everywhere, and only a few stories were given enough time to be effective.
PS: This is the real reason he was able to hang on to the power stone briefly in the first Guardians. Rather than vaporizing instantly like a normal human would. #InfinityWar
In #InfinityWar he is a self-appointed god, weary of gathering his children and doing what's best for them.