Because the protections that are in place for a very good reason, are not being implemented by those in power. I don't know why.

One needs to distinguish between three types of people here: AfD functionaries who draw up deportation plans, definitely fascist, core voters, generally inherited from the NPD, who vote for the AfD because of those deportation plans, definitely fascist, and then protest voters who vote for the AfD despite those plans. Also despite the rest of their programme.

Long story short in Germany the left parties have been captured by (at best) labour aristocracy and neoliberals at worst, their policies led to a severe lack of social housing, an explosion of precarious employment, and it's not like the labour aristocracy is above agitating against "freeloaders not pulling their weight". We have a gigantic precariat, many more are afraid of landing there, and a significant portion of that precariat is pissed enough at the establishment to vote AfD because it's the only party that hasn't betrayed them so far, or they want to show a middle finger to the other parties, or both, take your pick.

What's crucial now is that this protest moment is used to actually address those very legitimate grievances of the precariat. To invest in all that good stuff -- housing (now with great insulation), public transport so people don't need to buy expensive electric cars, district heating so people don't need to buy expensive heat pumps. No land in large cities to build housing on? Expropriate it, doesn't even need a change to the constitution. Pay for it all with wealth taxes which somehow have been completely cancelled when was it 90s? Suddenly all that anger that the AfD tries to redirect at immigrants will be gone, protest voters can stop voting for Nazis and clean their consciousness, and we'll all be happy (for the moment).