Think of it in terms of free software identity politics, or free software deontological ethics. In these terms lack of a multi-stakeholder copyleft (or single stakeholder committed to free software) invites identity crisis or immoral behavior, and presence of an enterprise (ie proprietary) version is identity crisis and is immoral. Therefore in those terms, the argument you're replying to is in favor of Kallithea.

If you're not thinking in those terms, the argument you're replying to might seem irrelevant, or even in favor of Gitlab, if eg you prefer a permissive license or the software you use to have a profitable business behind it. Maybe that's where you're coming from?