No, it's just plain immoral, not to mention short-sighted. American primary and secondary schools are also squeezing their teachers, by hiring Filipinos on J-1 visas, just like tech companies do with H-1Bs.
It's a bit like like making room in your fridge by pushing everything back, then adding new stuff. It works for awhile, but eventually leaves you with a mess of spoiled milk and rotten vegetables in the back. You can only strip-mine a hill for so long before it's gone.
I don't think STRS has had the same push for divestment, but they're known for taking a more activist approach. IIRC CalSTRS actually has multiple employees whose entire job is to lobby gun companies to change their policies.
Of course that sort of political and shareholder pressure is what led Smith and Wesson to start putting integral locks in the frame of their revolvers. That decision has had an almost universally negative response from their actual customers— those in-frame locks have a tendency to get rattled around by recoil and freeze the gun in an unsafe state.
All part of the game that got them into this mess in the first place.