Well yes, some groups. For crying out loud, here try this:the argument you proposed was some GROUPS of humans shouldn't exist: which is markedly different from individuals having shitty lives not existing in the first place
Except that wasn't the argument that was made, the argument that was made is the following:
"It is inconsistent to simultaneously hold the following beliefs:
1) Because some groups of animals have shitty lives therefor these groups of animals shouldn't exist in the first place.
2) Animals should be considered as equal to humans.
3) Some groups of humans having shitty lives does not mean these groups of humans shouldn't exist in the first place."
That argument is valid.
As for the numerous strawmen extracted from it, such as the one I quoted, well those aren't my responsibility.