This is the last place I would've expected to find people shitting on RFK.
Also, you can absolutely pin Vietnam on LBJ. (Of course, you can also pin it on JFK and Eisenhower too, but no one's comparing them to Lincoln) It happened on his watch! He was President! Negligence is simply not a sufficient excuse, certainly not when you have 500,000 (!!!) American troops deployed. The Gulf of Tonkin incident was, at best, a calculated misinformation campaign and, at worst, an outright fabricated pretext for war.
The Great Society is undeniably the high water mark for progressivism in this country. And I admire his ruthlessness in achieving progressive goals. I don't think that means we have to gloss over the rest, either.
It's one thing to claim that the ends justify the means. It's another to just gloss over LBJ's involvement - deliberate or otherwise - in Vietnam as some minor speedbump when it singlehandedly destroyed the progressive movement in America and irreparably fractured the Democratic party.