Try search for phrase "fakerom" or "fake rom" or "rottensys" with xiaomi.

The resellers get paid a few dollars for the malware install. I think the most common is people reselling to ship out to other countries, and not sold in China itself.

The aliexpress shops get shut down, negative feedback, but they just open another. Note that aliexpress actually shuts these down in the first place and is "reputable" end of things. Never ever buy devices from gearbest, wish, etc. - ever .

another reason being some eBay/re-sellers buy in low cost places (like India/China) - reinstall EU ROM and sell it at high cost. (Even now many devices in Asian markets come with a label like - Only for India-SIM)

Anti-consumer? By the capitalist businesses? Of course. It's just like buying crap from Amazon. If you use it you support it.