Let’s for the sake of argument, stipulate to all that you are saying with regard to the Olofson case - that it is 100% correct - that the weapon in question had non-standard parts and had otherwise been modified to fire full auto when the selector switch was placed in the (unmarked) full-auto position. You have obviously followed this case closely and you are geographically closer to the action than am I.
However, I on the other hand have seen the results when the BATF decide that they are on a Mission From God. I am warning you that they will, and have, manufactured cases from thin air. A little fast and loose with the evidence and the testimony seems to be acceptable to some of them when pursuing the Greater Good.
Let us consider for just a moment the possibility that you perform some of your own home maintenance. Got some pipe around? How about some electrical tape? Got an alarm clock? I see you are a black powder enthusiast (and a fine hobby it is). Let me come into your house with a search warrant and I guarantee I can find the components of a bomb. Thinking “Oh noooo. I’m one of the good guys! A friend of law enforcement, an upstanding citizen. Couldn’t possibly happen to me.” Right, until one of your fellow gun or bike enthusiasts becomes a government target, and they start looking for an informant to wire up. They will put your jewels in a vice - they don’t care. You would merely be a tool they need to get to the target and they will do exactly what I have described.
That's common anywhere. What matters is the facts of the case here, which does not provide evidence of institutionalized corruption.