My initial knee-jerk reaction was No, Jimbo is not gay, but then came the thought that something must have made Jack think Jimbo might have been receptive. Nowadays we'd call that gaydar, and presumably Jack's isn't very well developed.
I've wondered about Jack's decision to approach Jimbo too. On the contrary, I think Jack's gaydar must be
really good... I mean if for no other reason than he figured
Ennis Del Mar out! Also, the whole Randall situation was figured-out and handled in a few bats of his eyelashes across a dinner table. I think it's certainly possible that Jimbo is a super-closeted gay guy (and Jack had some clue about this through watching him in other contexts at the rodeo) who's terrified by his surroundings. I think there's a split second in the exchange of glances between Jack and Jimbo that might (and I do mean might) indicate that Jimbo is repressing a little bit of interest... But, I absolutely agree with this:
when he goes over the to pool table, he says something that gets the other guys to look at Jack in that mean way, and that just leaves a bad taste in my mouth about the guy.
Something about Jack's boldness in approaching Jimbo makes me love Jack even more. He just can't help being himself. He won't let the pressures of that bar/ environment hinder him in doing what is absolutely natural. His sense of recklessness is wonderful to me (if only I could be that brave), but of course in a bar like that it sadly can also be seen as scary and dangerous.
How would Ennis have reacted in a bar situation like that? Would he have behaved in a similar fashion to Jimbo if a guy (let's leave Jack out of this scenario for now) came up and started flirting with him in a fairly open way? If Jimbo is a closeted guy to the same extent or more as Ennis, can we imagine that their reactions would be more or less similar? Would Ennis have been more obviously intrigued than Jimbo? If Cassie had been a guy and had come onto Ennis (even with a fraction of the boldness that Cassie exhibits), what would Ennis have done?