I didn't realise that AIDS didn't get to be news in Wyoming - I'm used to national news in the UK, and had just assumed that the whole of the US got the news. Over here, it was big news after 1983 - I do remember people talking about it a lot. There were demos of how to put condoms on on TV, etc., and there seemed to be changes in the way casual sex was shown in popular culture (I remember that in the next Bond film, Bond was monogamous) - if I remember correctly we all had a letter through the door about it. It would have been impossible to miss it here, but if there wasn't publicity in Wyoming, I suppose Ennis could have missed it altogether - I hadn't even thought of that.
Thanks for the info, Chapeaugris. I feel that the timing did sidestep the issue before Jack's death - I really don't think it would be something Jack would have considered much. But at the same time, it puts Ennis's slow-dawning awareness and acceptance right into the AIDS era.