There is also the "Putin's boot isn't the one on my neck" factor. I don't dislike Putin nearly as much as I would if I lived in Russia ...
Well civilians in Syria who are killed by Russian forces seem to be of less interest for many libertarians than civilians who are killed by US forces. Makes no sense.
But it does make sense - precisely because of the "Putin's boot isn't the one one my neck" factor that I mentioned.
Putin is a statist goon. But we've got our own home-grown statist goons to worry about, like John McCain, etc.
There might not be much we can about the latter, but there is even less we can do about the former.
IOW: The boots of McCain & Co. are more proximate to our necks than Putin's are. So naturally, Putin's depredations are of less interest to us.
That is (one of the reasons) why our home-grown goons tend to catch a lot more flak from us than Putin does.
Like Origanalist said:
Russian forces aren't operating with our tax dollars or in the name of defending our liberty. It's not really very complicated. I don't think anyone here is under the delusion that Putin is a good guy.
And then there's the fact that the US is pretty much the premier bully of the world. Russia, China, etc. do not engage in forcible interventions in other countries nearly as often as the US does, or on anything like the same scale. Thus, as a simple matter of quantity and scope of aggression, the statist goons in the US are a more deserving target of criticism than the statist goons in Russia, China, etc. (at least on the issue of foreign intervention).
I'd be willing to bet that if you took some kind of global survey, you'd find that there is more anti-US sentiment around the world than there is anti-Russia or anti-China sentiment - and not just among libertarians, but among everyone in general.