I don't think it's an exaggeration to assert this sort of legislation is the thin edge of a much more concerning wedge in terms of being able to speak freely.
And who defines what a 'reasonable' person is???
You could be in a public space having a discussion with mates and say 'tbh I can't stand x people' with x being whoever is being discussed. There could be a 'reasonable' person within earshot who thinks 'MMmmm, that comment wasn't reasonable and could stir up hate' so they call the police?!?
Fine, 9/10 no action might be taken, however the whole ethos behind this legislation is dangerous.
And PLEASE, don't anyone say 'but if you stay within the rules you have nothing to fear' that is one of thee scariest stances to take for a whole lot of reasons!