I think you're being way too sympathetic to the man here. While obviously the system is rigged against men and his suffering was likely a large part of his mental instability, the fact that he killed his kids is still horrifying and inexcusable no matter the circuмstances.
I agree with all your conclusions(that marriage needs to be more permanent, divorces are rigged against men, these horrendous divorces cause these murders), but your lack of a condemnation of the man is I think what made it sound MGTOW-ish to Matto. He's still guilty for his evil actions no matter how hard his life was.