Lets look at the underlying law and past practices.
Fed law allows a person to manufacture a firearm, for the own personal use, without needing to comply with all the requirements a commercial manufacturers needs to.
Generations of custom riflesmiths made small numbers of guns every year without needing to meet the requirements for being a "manufacturer".
Along comes the AR, and its design allows for simple assembly without gunsmith skills. Ok, fine, you buy a parts kit, and you buy a lower receiver (which is, under the law, the firearm) and put it together. Govt is fine with that. You bought a firearm and followed all the applicable rules.
Then along comes the unfinished lower receiver. I don't know who, or when they decided 80% was the cut off point, but it wasn't a firearm. Once you finished it, it was a firearm under the law and the standard rules applied.
As long as it remained in your possession, the govt didn't care much. You are allowed to sell it (if you got tired of it) at which point it needed a ser# and all firearm rules apply. You are not allowed to make them for sale.
(and yes, some people didn't follow those rules. When caught, they got prosecuted)
You can buy a kit with all the parts (finished receiver) and the jigs and tools needed and that's not a problem IF it is sold as a firearm.
The issue here seems to be that the ATF is looking at a kit with an 80% finished receiver, and all the other needed parts as "readily converted to" being a firearm, and if such kit is not sold as a firearm then its sale is a violation of the law.
In the past such complete kits weren't sold. Finished receivers were sold as firearms and unfinished ones were not. The rest of the parts were sold separately, and by doing so, no laws were violated.
I would point out that in this matter, right now, we do not KNOW with certainty what charges will be brought, or even if any will be. Right now, all we know is that the ATF raided a company selling 80% lowers and all the other needed parts as one kit. People are speculating on what the justification is, and why now.
We won't know that, until the matter goes to court. Personally, I wouldn't trust any ATF official's statement at a press conference even if it was to announce that the sun would rise tomorrow...
They can, and do say anything, what matters is what goes on in Court.
And, please, recognize a couple things and exercise some restraint before automatically condemning the ATF for violating our rights...
The first of which is, that the company raided might actually be breaking the law. The other thing being that the fact of the matter, breaking the law, or not, WILL BE DECIDED IN COURT (assuming it goes that far) and not in our forums or by ATF fiat.