Unless of course the support provided by a (Western) outsider had caused other tensions (warlords uniting or what have you), thus increasing the body count, which is one possible outcome out of many.

Genocide tipping in exactly the opposite direction is another (obviously unintended) possibility. Oh yeah... The rest of the wiki you link talks about that... Oops!

You can't predict a future that didn't happen. (Again unless you're The Doctor).

If you believe the judicious provision of weapons is a worthwhile humanitarian endeavor, then by all means create an NGO dedicated to the task. I can certainly envision donating to such a charity. Please don't involve the USA military-industrial complex in such a Faustian manner.

Also it isn't so convincing to link to a wiki section that supposedly proves your point about reducing bloodshed, while the very next section on the page describes 5 million people killed in the same area in the following decade.