Most (not all) people who commit suicide aren't in their right minds and aren't thinking clearly. Denigrating it as being selfish misses the point of what's going on for the person.

it accomplishes nothing

It accomplishes nothing for you. For the person committing suicide, it frees them from significant pain of some sort. That might be psychological pain due to a disturbed mental state, but it's still pain.

Guilt is a hard one and you have to learn to deal with it and move on, but blaming the victim isn't going to help there.