Alimony isn’t fair

I saw a post here of a woman who is SAHM of two kids saying that her husband wants a divorce and that she is terrified of what’s going to happen to her now. Everyone in the comments was saying things like “that’s why women shouldn’t marry and be SAHM” or “that’s why marriages lasted longer in the past, men wanted to women to be dependent”. With these points I agree but they were also saying she should get alimony on top of child support(if she gets custody) which I find insane. Why should an ex husband or wife have to compensate for the other person’s income. Especially when the other person wasn’t working. For a person to make enough to support a family of 4 they would probably need to work many hours a week. And I just don’t understand why should someone keep financing their ex spouse after divorce, if not for their kids of course.