I found this movie more a comedy than an "antithesis" for High Noon. Seemed like John Wayne just wanted to play "Cowboys and Bad Guys" than make a serious movie... One thing I don't understand - if John Wayne hated High Noon because Gary Cooper had to ask for help to do his job, then why did Wayne have Stumpy, Dude, Colorado, and Carlos at his side, plus ask Wheeler's men for help?
shareThose guys volunteered to help Chance. Unlike Will Kane (Cooper) in High Noon, Chance (Wayne) didn't go around asking them for it...although, since Stumpy was working in the jail already, it was really his duty to help out, though I'm sure he never thought of it as a duty.
You're also wrong about Wheeler's men -- Chance didn't ask a single one of them for help. In fact, at the hotel bar when Wheeler volunteered his men to help out, Chance specifically rejected the offer, calling them "well-meaning amateurs, most of them worried about their wife and kids." He even rejected Wheeler's own offer of help.
As for Dude and Colorado, both got involved as circumstances demanded, after Burdette's men made them enemies by their actions. Carlos (and even Feathers) got into it of their own volition as well, just because they were Chance's friends -- and you'll note that Chance didn't want their help either and did everything he could to discourage them.
I think Rio Bravo is a "light-serious" movie. Obviously it doesn't have High Noon's portentous, self-important "meaning" and pretensions (it's good, but it is a bit heavy-handed), but at base it's a serious movie with some light or comic touches that work well in the film. It may be something of a counter-point to High Noon but it wasn't intended to be some deep "message picture".
There may have been others but I consider Rio B' the first pop Western. Martin and Nelson were major stars away from film. This had its light moments --like telling Dude he smelled bad-- but I wouldn't call it a "comedy."
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