It's not an ok thing to do here, regardless where it fits (or not) in the list of logical fallacies. There's a whole section in the site's guidelines about this under 'In comments'. The comment in question flunks just about all of these.

https://news.ycombinator.com/newsguidelines.html

Still doesn't add anything useful to the conversation

It literally does. Whether someone has a stake in an argument does not affect whether it is true or false.