There was a legal analysis in a major newspaper the other day. Some potential issues that it considered were: public incitement of criminal acts (violence, doxing, property damage), incitement of hatred, endorsement of criminal acts (shout-out to convicted left-wing extremists).
The analysis weighed these issues against artistic freedom. The conclusion was uncertain but emphasized that (a) the artist's simplistic assertion that all is "covered by artistic freedom" does not hold in this general manner and (b) that most of the potential issues are in a grey area and can still be seen as protected by artistic freedom, depending on how one interprets the piece overall and some legal constructs (e.g., whether neo-Nazis are a "group of people" in the sense of anti-hate laws). The clearest issue they identified was the one about property damage (graffiti) and with less certainty the one about incitement of hatred.
For the German speakers, I am posting the link to the article, but it's paywalled: https://www.zeit.de/feuilleton/2026-07/keine-angst-danger-dan-igor-levit-recht-kunstfreiheit-antifaschismus
Personally, most issues I would consider to be (still) covered by artistic freedom. But it's a slippery slope (What if this was a right-wing song?), and I also kind of understand why the TV station decided to back out, although I agree they could have done that differently.