It's been going on for years, I know that. I don't know if the rent-seekers have ever tried to shut it down. The fact that it's so complete tells me that a huge number of mainstream law firms look the other way when their employees use the browser extension.
In the case of PACER, they are public records, and have no copy right attached to them as they are government documents, the government can not hold copyrights by definition everything the US government produces public domain.
So was the FBI. They harassed my friend Aaron for a year when he started snarfing PACER documents from public libraries. In the end they had to conclude it was legal, so they couldn't prosecute him for it; instead he was persecuted by different US Attorneys for downloading papers from JSTOR until he committed suicide.