As to being anti-US, am looking at what level this opposition stems from.
Is it strategic or tactical ? Does not count if its tactical.
In the case of the LTTE, their sources of funding came under severe strain after the passing of US laws post 9-11 that curbed financing terror orgs.
PKK's opposition would stem from US moves against them in Iraq at the behest of Turkey.
That the US classifies the groups you mentioned as terror orgs, it is more the US drawing the line against them as opposed to the other way around. That is to say these groups were not anti-US before 9-11.
Doesn't this count as more left than right ?
There is an authoritarian parallel here with the fascists.