@maxdancona,
1. I don't think a plumb speaking role at the convention is what Bernie is talking about when he says concessions. He means Hillary changing her policies to suit Sanders, and since Hillary has won the primaries because of those policies over Sanders, that would not be a good thing for her to do.
You don't know at all that Secretary of State was offered in exchange for Hillary's support, that's conjecture. And besides, even if was true, which we don't know that it was, it didn't come at the end of Hillary publicly asking, "What concessions is Obama going to give me to entice me to give up the race"? Because that is what Sanders is doing.
2. TYT, which I have watched with decreasing frequency for a couple of years, has gone whole hog on Sanders. Hillary can't do anything right as far as they are concerned. I'm not sure they represent young voters, as ehBeth pointed Hillary does fine with young voters when compared to Trump.
3. Hillary's whole campaign has been reaching out to voters. I see no reason why Bernie can't be given a good speaking place at the convention, but any concessions should be made when the two get together. Publicly calling for concessions is just bad form on Sanders' side.