Of course it isn't offensive.
I would be embarrassed to be offended by someone dressing as Jackie Chan (even if they had to change the colour of their skin).
The people on the float weren't trying to offend, mimic, belittle or insult anyone. They were emulating characters based on admiration. It's a compliment.
Are men who dress as women on stag nights offensive? Given the 'straight, white male' slur often used, surely it's as insulting. Those men don't know what it's like to be a woman!
The perma-offended love telling others what is okay to say and do and think but life doesn't work like that and nor should it. Think about the backlash in the states.
Pretending to be liberal but with a heavy slant on thought-crimes, PC-ness, safe spaces and no platforming, it's hard to take them seriously.
I don't feel the need to distance myself from racism. Why should I? I don't ahve a print out of my CRB check on a t-shirt to distance myself from actual criminals.
Besides all of the hysteria and calling this a hate crime, everyone has missed the point and that's that this was politically motivated and a rush to challenge the other councillors to see who could be most offended.