I think that was an inadvertent juxtaposition of the words "just" and "allow": the GP probably didn't mean that links to articles should be forbidden, and only subjects for discussion ("titles") should be allowed to be posted.

At least I read their comment as "I often wish HN would allow, besides links, just titles to get posted and HN folks just have a discussion around that".

Would you still wholeheartedly disagree with that, too?