I am not British so I could be viewing it wrong, but I imagine they are calling Dyson a terrible person because he advocated for Brexit, and now that it is happening, he packed up and moved to another country and won't feel any repercussions for something he advocated for.

Any evidence he wouldn't have done the same thing if brexitbhad failed? Would Asia stop being an important market if the UK was in the EU?

Again, I have no skin in this game, but if I did then I would say the only thing that matters is what he did do, not what he would have done.

But everything every brexit supporter has done since 2016 could fit that bill. Unless brexit triggered him moving the company to Singapore, it doesnt make sense to count his brexit support as relevant.