It's not US. I heard it here, from my mother, aunt and grandmother in the 80s and many times since. It makes perfect sense to me. And as I keep saying, the Indian community manages it without faff, complaint, offence and moralising. Red is the bride's colour and guests don't wibble and whine and ask if this colour is too red, if this sari has too much red, if they wear red it's the bride's moral failing if she's offended etc. They just wear blue, purple, orange, green, anything from the zillions of other options available. It's not hard!
I've noticed a massive resistance on here from people who somehow never heard this rule (I still don't know how) and I don't understand it. Ok, somehow it passed you by, but once you know about it, why wouldn't you just wear any other colour? What's with the furious need to reject it, to insist everyone who knows about it is making it up, to demonise the bride if she's upset because you deliberately flout etiquette, which is pretty much the definition of rudeness?
Is it because people don't want to accept they've made a faux pas in the past and it's easier to claim it was never a thing or it's all the bride's fault if they upset her? Just wear something else!