@cataspanglish
For once, I'd prefer the assailant weren't a fascist, if only for the fact that any charging up of the current debate in Poland with more partisanship risks to drive the county towards starker polarisation. Up to the point were one half of the population takes up arms against the other.
On the face of it, the hate speech probably emboldened an already deranged individual in murdering the mayor, so - diplomatic spin aside - you are spot on with your characterisation.