"What is relevant is Donald Jr's INTENT. In his email response (I am paraphrasing, but you can verify) he says, if the offer of dirt on Hillary is true, I love it! The intent behind this statement is loud and clear."
I agree with you that this is the heart of the matter, and like you I am surprised that the so few of the anti-Trump people have zeroed in on this crucial element. Good on you for bringing it front and center. Let's take a look.
Trump jr gets an email that says, "We've got dirt on HRC from the Russian govt, and we want to share it with you as part of Russia/Putin's effort to help Trump win the presidency." (This may not be absolutely the precise wording, but this will be the most aggressive/damning "parsing".)
Then Trump jr says, "I love it, bring it on." This will be spun as Trump jr declaring his willingness and his INTENT (your caps) to collude, and as the very first substantive act in the process of collusion.
However -- now the case for the defense -- after that, it's all a giant nothingburger, because beyond the emails there was absolutely nothing. Nothing at all. Nothingburger because (1) intentions aren't actions, and (2) the "bait" -- "dirt on HRC from the Russian plan to install their Manchurian Candidate" -- was a total fabrication with zero connection to Russia. No Putin/Kremlin involvement at all. Just a fictional lure from a fat, ugly, British "publicist" political dirty trickster.
The Russian lawyer appears to have been a pawn. Her interest, the element that drew her into this silly little scheme, was her concern about Russian orphan adoptions. She wasn't privy to the content of the emails and didn't know anything about any dirt on HRC. She was a prop who provided "the Russian element", her Russian name.
Don jr's putative "evil intent" may make for a momentary kerfuffle, some screaming and shouting and more ratings for CNN and msnbc, but it has no political lethality. And it will end up a spectacularly embarrassing exercise in futility -- not that that will dissuade anyone. It will be futile to try and make a case for collusion out of Don jr's "I love it, bring it on!", because there was nobody on the other side to collude with: no Kremlin involvement, no Kremlin Manchurian Candidate plot, no HRC dirt. Nothing, nada, zippo, a phantom.
And, of course, no involvement with or connection to the President. So the only possible impact is that maybe Trump, his family attacked yet again, decides enough is enough, and dishes the wrath of god to various and sundry Swampistas.
Bottom line: when the dust has settled, the Trump opposition will be worse off than ever.
What a fabulous spectacle: the self-immolation of the corrupt American political system! I frikkin' can't get enough!