My main point is that we don't know for certain what happened in the meeting. It's silly to insist that the second possibility is the only one and shows Trump Derangement Syndrome.
Personally, I think the first one is the most likely. It fits the known events the best. The Left is grasping at any contact with anyone from Russia as proof of collusion. Some people on the Right are doing the same thing with the Obama administration's tapping of Trump communications.
3) The meeting was a set-up by the group doing opposition research on the Trumps in order to provide an excuse for the Obama administration to monitor the Trump campaign. The Lawyer claimed to have dirt on Clinton then changed to the adoption story once she'd gotten her meeting. As I mentioned before, the lawyer has as many ties to the opposition research group as to the Kremlin. Also, she was allowed into the country after her visa had been rejected. The timing of the requests to monitor the Trump campaign match this scenario as well as the release of the emails matches the second one.
2) The lawyer made an agreement to release DNC emails in exchange for some concessions. That's a lot of negotiations in a single 20-minute meeting with no known follow-ups or face-to-face with Trump, Sr. Still, this is the story that the Left and the press believe. The closest to proof for this is that Grucifer 2 released the DNC emails shortly after the meeting.
1) The lawyer lied about having dirt on Hillary Clinton in order to get an appointment to talk about her pet cause, adoption of Russian children. This is Trump, Jr's story.
So, what are the possibilities?
Simply trying to get background information, even information acquired by the Kremlin, is not unusual. The "Trump dossier" that was publicized shortly after Trump was inaugurated was supposed to contain KGB information and no one blinked an eye at the DNC being involved with that. No one was bothered by the DNC doing opposition research with the help of Estonia, either.
Given the known facts about Donald Trump, Jr's meeting with a Russian attorney, I can think of three possibilities. I'll list them below but first I want to make a few observations.First, the term "ties to the Kremlin" is kind of like "degrees of Kevin Bacon". Virtually every highly-placed person from Russia will have some sort of ties with the Kremlin. This is part of doing business. The lawyer also has ties to the group hired to do opposition research on Trump, Sr, for rival Republicans and later the DNC.