In regard to sniping coms, the traditional explanation is that it's a moral victory. I personally think it's a disruption thing. If a com is on the front lines, it's almost certainly part of their expansion or defense plans, on top of the 4m+6e. Other than that, I think it's kind of conditioning? You kill the com you get a big congratulatory explosion, you feel good. It's also easier to box and click a commander than it is to clone ravens onto mexes. Finally, com killing is more opportunistic. When you see a com overextend you might not get another chance, but the mex will always be there.

I don't think there was anything wrong with Sanyc killing the com in this scenario (other than the questionable decision to go ravens vs. LV in the first place). Has sanyc played recently? Their style feels 'old' and I think I remember them leaving a while back.

I haven't seen sanyc recently, and according to their battles page they haven't played much since a year ago. They've been playing a few dozen games in the last two weeks, and played a dozen games half a year ago, but otherwise nope.

Also, yeah, the commander snipe in this case made sense because it stopped the defense push, which is the main time I see it as useful once players are above +30m.