People will always get criticised, whether good or bad, what matters is taking the decision which you feels is good form your, you aren't living anybodys life, Klopp's decisions to return to football activities after couple of months should be no one problem regardless of what he said initially, and after ending almost a decade contract with Liverpool.
I wonder why the hate or criticism, I guessed majority are just jealous and would have wanted him as a coaching consultant for their club or any other thing as long as he is with them, since everyone can agree he is an excellent coach, guess we can say a great one.