Yikes sounds like a bad situation all around.

I don't mean to pour any gasoline here, but you should definitely ask to swap first. I've done the same as you many times but always, always asked the ISM in advance pre flight (and always said okay). Once they're on board eith what you're doing no risk of your situation occurring.

Also, just a heads up but never hand the forms to the crew. Ever. (Unless you specifically want them to read). Even if you seal them, the crew almost ALWAYS open them and read them. Usually only good reviews are passed along and bad ones thrown out.

As for your charge of racism, yikes. It's a very serious accusation and it doesn't sound like you have proof! From what it sounds like to me, the ISM was pissed you didn't show him/her the respect and perhaps is an insecure person. I mean, you were probably the only person in J doing this unique thing is switching seats on that flight, and maybe the ISM is a control freak. I sympathize with a bad flight but I think you really haven't explained why the ISM was racist! Which undermines a bit of what you've written, at least IMO. Having lived in HK for a decade, I've noticed there is a strong (and somewhat unfortunate) undercurrent in HK whereby folks like to accept as fact CX (and SQ) female crew treat Caucasian men amazing, and everyone else dirt, with an implied tone that the CX/SQ/etc Asian female crew are all gold diggers looking to find a foreign husband. This is quite the unfortunate stereotype for many reasons, least of all I don't see a whole lot of actual proof of it being doled out selectively (I fly with mainland and HK colleagues frequently, and feel comfortable saying a degree of flirting / etc. goes on between everyone....good or bad. I will say that a charge of sexism might be more well placed!). But this always makes me uncomfortable when I see a whiff of this argument. Anyway I'm not sure if that's your point, maybe the ISM was a guy!!