Literally never heard of them. With all the random bullshit companies dumping crap into the market, if you don't have good name recognition these days, it's just assumed you are some random Chinese product clone with dubious quality.
This is fine when I purchased my knockoff Dyson vacuum that still works great, but I wouldn't trust all my data to a company I dont recognize.
Naw, it was most commonly used as a term similar to "that chinese guy" which is easy to confuse with racism at a time period where people were generally racist towards the chinese, but the term itself is not racist. There were actual slurs back then they could use if they were about that.
My Grandmother said they always bought they're vegetables growing up from the chinaman who rolled his cart through the alleyway behind their homes. It's not a term of hate, but it's easy to say hateful things alongside it.