Virtually every kind of "fun" creates pollution. Even going for a run you pollute. What about doing a road trip in a modern car is "better" than putting around town in an old one when both activities pollute a similar amount?

The real questions worth asking are:

1. Are these classic cars a threat to public health? (Presumably no, their numbers are small and ever dwindling)
2. Should the law apply to all cars and when/how is it fair to make a carve out? (The answer is subjective and political and I have a feeling this is the one that actually struck a nerve with you).

Also worth noting is that EVs are hardly a panacea. Modern ICEs are "good enough" that a lot of the immediate health concerns now come from particulates from brake and tire dust, noise pollution (which EVs contribute to nearly as much as ICEs at speed), sedentarism, accidents, and hostile urban design. The real fight is in getting most passenger cars eliminated from cities altogether and rehabilitating suburbs to be livable without car dependency, not in bickering about powertrains.