In today's Germany, it is rather unusual for a politician to repeatedly use Christian festivals as an occasion for messages. The Governing Mayor of Berlin is apparently outraged by this – and even more so when he wishes "all of us and our guests" relaxing days.
If the Greens and the Left conclude that "Kai Wegner regards non-Christians merely as guests", then this is a rather German interpretation, namely an unlimited one.
The largest possible gun
The additional accusation of racism was to be expected – apparently it is no longer done under that. At best, if you want to look at it that way, it was about a different approach to different religions – for understandable reasons.
A different treatment of Germans and foreigners is sometimes even prescribed in the law itself – on the other hand, it is not automatically racist. Because that would mean that every non-German belonged to a single "race". Whoever brings out the biggest possible gun right away should not be surprised if at some point he is no longer taken seriously. Real racism is thus trivialized. But unfortunately there are entire professions, even a kind of industry, which live quite well from the compulsive use of the stamp "race". This is not progress.