I've often noticed much the same reaction, and it has left me just as baffled as you.
However, I do have the feeling that something has changed within the last couple of years. When I talk to Thai friends nowadays, even those who used to be apolitical/indifferent do tend to have an opinion now. And are usually very firm and outspoken about it. Some have also switched sides over the years; I did have the impression that Khun Yinluck was quite popular at the beginning of her term, even among those whom I wouldn't have put in the TS/Red Shirt camp.
I'm actually less concerned about the military than about the increasing polarization and determination of 'ordinary' people. The military will or won't do their thing, and if they do, some people will die and that's probably the end of it for a while (based on previous coups). What worries me, however, is the many violent clashes between opposing groups of more or less regular folks, and not just in Bangkok. Far too often something that should be limited to a verbal exchange of arguments leaves people injured or dead.