Security measures never prevent all abuse. They raise the cost of abuse above an acceptable threshold. Many things work like this. Cleaning doesn't eliminate dirt, it dilutes the dirt below an acceptable threshold. Same for "repairing" and "defects", and some other pairs of things that escape me atm.

That's the same argument as CAPTCHA's - as far as I know there are no bots protesting them making their lives harder, but as a human - my life is much harder than it needs to be because things need me to prove I'm a human.

Clean for data ingestion usually means complicated for data creation - optimizing for the advertisers has material cash value downstream, but customers are upstream, and making it harder is material too.