I suspect every single flag in the world will cause offence to someone, somewhere. Sort of the nature of the beast. They're tribalistic, thus a little bit shit, but also very empowering. A bit like football really.
Think whoever chooses to fly a flag in public should be very clued up on its...
Isn't that the whole point of flags though... To 'flag' something?
I'd say it's probably best for anyone intending to fly any flag in public to in fact have a detailed encyclopaedic knowledge of the history of said flag, then making their mind up from there.