I doubt it is the trade war. I think it is his attempts to interfere in European politics. Musk has done this in both the UK and Germany, and is signalling doing this in other places.
In the UK trying to help an extremist most people loathe (Tommy Robinson) is not going to make you popular. I am guessing that in Germany a lot of people loathe AfD so there is a similar, probably stronger, effect.
From a UK point of view, even if Trump imposes tariffs on our imports, that might be a problem, but it is not repulsive in the way backing an extremist is.
In the UK trying to help an extremist most people loathe (Tommy Robinson) is not going to make you popular. I am guessing that in Germany a lot of people loathe AfD so there is a similar, probably stronger, effect.
From a UK point of view, even if Trump imposes tariffs on our imports, that might be a problem, but it is not repulsive in the way backing an extremist is.