No-one said he is a Nazi, just that he's a fascist. There are multiple different flavours of fascism – it isn't all literally shooting people in the head and ordering thousands of people into death camps, it can be more subtle and insidious than that.

Also worth mentioning that fascism generally doesn't start with the ethnic cleansing and mass murder, it starts with things like; scapegoating minorities, being overly tough on crime, and peddling misinformation. It takes quite a few years for the fascists to gain enough power to be able to enact the kind of policies that are generally pretty unpopular among normal people.