I've blamed the refs before, but for this game, bitching about the refs is Beamer-esque. Other teams, once they learn cut blocks aren't illegal chop blocks, swear our blocks are 9:30 or 2:30 illegal blocks (only 10 to 2 cut blocks are allowed). Tunnel or bubble screens will get the benefit of the doubt even if an OL is 3.5 yards.
The exact rule is confusing. This answer says there's no exception for screen passes, but I think the rule says the rule only applies when there's a pass across neutral zone. So a tunnel screen, which is always caught behind LOS, cannot have an ineligible receiver downfield.
http://sports.stackexchange.com/questions/8549/what-is-meant-by-ineligible-receiver-downfield
As far as the targeting call, it comes down to "life isn't always fair." It wasn't fair either that we had a long pass called back because #75 lost his feet. And unfair calls are sometimes in our favor. For when #75 lost his feet, he didn't mean to block defenders in coverage, which is what the rule is there to prevent. But it's hard to write the ineligible receiver downfield rule to read the mind of OL. So the hard and fast three yards rule is used.
To prevent head-to-head contact, you've got this draconian ejection rule. But, IIWII. The call in the Duke game was far more questionable, since the DB lead with his shoulder.