I wouldn't actually knock him for this given the issues pro cycling has in Germany.
This is a country that has effectively turned its back on the Tour, so Kittel finds himself in a position where he is achieving success and having to answer for the credibility ofthe sport.
We have Sky being accused by the French of being juiced, even after supplying data on Chris Froome to an expert nominated by one of their newspapers.
He has declared what he was involved in when he was a kid, but that was a world apart from the current situation. He is making unequivocal statements about jailing cheats. Not sure he can do a lot more.