The rules are (surprise!) the exact same as in the real world.
So stop censoring yourself so much. Just post what you want to say. There are only two reasons you shouldn’t:
A) You wouldn’t speak to people like that in real life.
B) You aren’t excited about your own idea. Not even a little bit.
If either of these reasons applies, please don’t bother us with your post.
Now, of course, if you decide to operate by this principle, some people will hate your posts. Because (another surprise!) your ideas won’t always be to their liking.
And here is the main point: this is a good thing.
You didn’t publish anything completely crazy, because it’s something you would actually say to another person in a professional environment. So, it’s just your opinion, and someone else happens to have a difference of opinion.
That is actually great, because now you get a ton of visibility thanks to the productive discussion under your post. It is much better than remaining invisible, wouldn’t you agree? And in the end, you will either make your point or learn something new from others.
Either way, you are better off.
The absolute worst thing you can do is publish defensive “blah blah” with no real value, emotion, or story behind it. That is what truly looks stupid out there.