They’re recommending a meme-distro in a serious thread without making it clear that it’s a joke.

In this case someone might read their comment and follow their advice, thus ending up with Nyarch as their first distro. In the future, when they run into problems, they’ll have trouble finding support because it doesn’t have a massive knowledge-base or the support of a big community behind it like all the mainstream distros do.

It might be an obvious joke to a Linux user, but a total Linux newbie might get confused or not even recognise it as such. If this comment was posted in /c/linuxmemes or something I wouldn’t say anything, but it is not.