I believe if you have an "alternate" thought to the original thread, unless it is "your" thread in the first place, then you ought to start another one about your additional thoughts. Especially if you and another person are enjoying one another; the two of you can "start over" in another thread and then go wherever you want.

If someone wants an opinion, I think that is just what it is and is not non-supportive just because someone doesn't "like" it. I'm always reminded of the comedian Gallagher who told the story of how a teacher asked his opinion on a paper or test and he gave it and. . . got an "F". An opinion cannot be "wrong", supportive/non-supportive, it just is someone's opinion. I think people posting need to be clear on if they are asking for people's opinion and advice or people's "support".

The biggest felony I see on boards is that people don't realize they are talking one-on-one at all times. If A asks a question/makes a statement, asks for opinion, etc. and B comes along, B is responding to A. It's bad form for C to come along and talk to B in A's thread, especially without frankly stating, "Hey, I'm talking to B here but I know it's A's thread". Threads get muddied because people think a thread is a "group" thing and it's not; one can only talk to one person at a time, one-on-one. B is not going to read/respond to A the same as C is so B getting in C's face for responding "wrong" to A is out of line; that's A's job only.