One Kristofferson denied it ever took place. He's a brave enough bloke to have said it though.
There's a good article in the NYT about Toby Keith (paywalled). Suggests there was a bit more to him than those songs from the post-9/11 period.
A lot of country songs can appear to walk a line to that regard for some, but I think people tag many of them in a way that misses the point. I like Trace Adkins' 'Somewhere In America' track. It ticks every 'yeehaw' cliche but it's actually an uplifting song in many respects.
And, in the midst of everything going on in the world, lines like 'we stand for the flag and if you don't like it, we don't care' from Riley Green make me smile if only for how some people lose their mind over them.