Releasing files of black ops you did 50 years ago is not being open about it, the US would never publish black ops they are doing now because otherwise it would undermine the effects of such proxy wars. Furthermore, much of what we now is not so much releasing that information but because there are brave whistleblowers who release information regarding the war crimes.
Still, I don’t see how the fact that some other countries do maybe similar stuff, since again it is all theories since until information is released we cannot confirm anything (not that I doubt some countries do fund military groups) that doesn’t make my statement that the West has the biggest and most illustrious history of funding terrorist groups in what they deem enemies of the West.