It isn't a question of suppressing discussion, as you'll see if you look at the voluminous threads HN has had about that (see https://news.ycombinator.com/item?id=22132714). It's just a question of what's on topic in a given thread. If you allow a hotter topic with greater mass to enter into a smaller thread, the discussion will get sucked into its gravitational field. That approach leads to all threads being dominated by the same handful of hot topics over and over, so we try to avoid that here.

Re "taking one side": it always feels like mods take the other side. The people on the opposite side from you feel that we're taking your side; I guarantee it.

Your comment was perfectly natural. It's just that we know from experience what sort of thread that would likely lead to, as I explained at https://news.ycombinator.com/item?id=22140452. Stack Overflow is much larger than the OP's fledgling community, and the recent controversies about it have burned pretty hot, so it could easily have become the dominant topic. That wouldn't be fair either to the fledgling community or to the HN community, which benefits more from having a new discussion than repeating an old one.

Also, I don't think it's really fair to the OP if we start putting her on the spot about Stack Overflow. She probably hasn't thought that much about it, since for most people the only way to get a project like this off the ground is by focusing on one thing for a long time.