These people would be surprised how many people have preserved multiple portraits of Hitler and hidden away in their homes and shops. I'm talking about stamp collectors. There were very many stamps issued with Hitler's gave on them, and very many casual to dedicated collectors own at least one.
Having a shrine to Hitler is not fine. Owning historical items in context is totally fine. Authentication and appraisal is a normal part of insuring any kind of collection.
The real issue is not that a politician has one Hitler-related item amidst a wider collection of rare, historical items, but that someone who is independently wealthy and can spend millions of disposable dollars on a hobby is representing "the people" in a time of rising unemployment, affordability crisis, housing crisis, cuts to essential services, etc.