It's not but it does have a long history of being applied to vilify any immigrant group. In the early 20th century the US was forcing all crossers from Mexico to go through a delousing with Zyklon-B because they were 'dirty' and threatened to bring in vague disease. OP wasn't saying clean is exclusively a bigoted phrase against Chinese people, it's more broadly problematic and directed at any group considered undesirable.

https://www.zinnedproject.org/news/tdih/bath-riots