I think it's the height of arrogance to suggest that a viable candidate who's won a number of delegates should give up more than seven months before the election and four months before the convention simply because the other candidate, at this stage of the game, SEEMS like the inevitable winner and Hillary might "ruin" things for him. Both Bernie and Hillary are in it to win it. Why not allow the campaign to play out normally just like every other campaign and let the PEOPLE decide who they want? Sheesh.
I also detect a bit of sexism here. It's typical in patriarchal societies to pat the little lady on the head and condescendingly ask her to step aside and let the more "competent" man take over. The minute Bernie decided to run, the media started treating Hillary like, well, her campaign was okay while it lasted, but now that a MAN has a real chance of winning, she can't possibly beat him. Well, screw 'em. The campaign ain't over til it's over.