That sounds like the decision of an FBI official, not the AG. Perhaps the FBI director or deputy, but probably the SAIC of the local field office. (Was he known to be armed?) I suspect this also happened right after agents were killed in a raid during a Florida CSAM case (I think that case was in 2021.) so they might have been a bit more cautious or overzealous.
Because they were making threats against public officials (school board members). (Again this is probably within FBI and not at the top.) Some of these "threateners" that get wrapped up in the RW complaint weren't actually parents or in the communities, but roving bands of PBs and their ilk who went from school to school getting shouty school board meetings because the school had the temerity to treat LGBT children as humans.
I already told you that the "jail for years w/o charges" was a lie someone told you. Everyone was charged *before* they were arrested. You should stop repeating it. Now I will add that misdemeanor trespass (the walking through the building crime you mention) didn't get anyone more than a few months sentence (after conviction), and I am aware of anyone in that category (out of about 1000) who was even detained for more than a couple days after arrest.
You have been fed some very nonsense falsehoods about Jan 6th and the prosecution of the crowd. You should treat your sources as if they are lying to you, because they are.
Who?
Using a credit card near the Capitol was not a crime and no one was charged for it. There was no place to use the cards on the grounds since everything was closed. Hotels and CC companies, etc., were given data retention orders, but the FBI was not just given a list of credit cards used near the Capitol to comb through. What they did get, through a warrant, was the list of all cell phones that were geolocated inside the closed Capitol grounds. These were used in many charging documents, but only with additional photographic evidence of the suspect inside the Capitol.
Here's the thing, even if everything you said was completely right (and basically none of it is, but let's put that aside), it would not justify the violation of anyone else's civil rights, including due process.
Your narrative is completely false.