It seems kind of silly to have to write a message here that someone has provided an answer for on another thread, but their answer didn't work for me.
I fail to see why 200 people reporting a problem individually is better than 2 or 3 (where the software vendor might be able to solve everyone's problem in one fell swoop).
The general respose of "please post your own thread" is not arbitrary, nor incorrect. It's there for a very good reason.
As you stated, somebody else posted an answer, presumably one that worked for them. However, this answer did not work for you. Now, wouldn't this point to you two not actually having the same exact problem, but rather different problems with similar symptoms?
A lot of problems posted in these forums are like that. Somebody can have a problem and then others come in with "me too" responses. Unfortunately, they're not the same problem, they're just the same results from different but sometimes related problems. This sort of cross-talk and communication makes it difficult for knowledgeable persons to be able to efficiently help people. Having a dozen voices all saying me-too's and similar tends to raise the noise level, and drown out the signal.
We ask that people post in their own threads so that their specific problems can be solved. We ask that people not post their problems in other people's problem threads so that they don't overshadow the original person's problem and lead to them not getting helped efficiently.
You're free to disagree with this practice. But over time, we have found that it does work best and is most effective at getting the right answers to people with issues, when those answers exist, and when people focus on solving the issues brought up by the original poster with minimal cross-talk. If you have answers, or the ability to offer debugging assistance, or in any way can *help* contribute to somebody's solution, then by all means post in their thread. But "me-too" responses will get this sort of reply from one of the moderators. They're trying to help you, not to shut you down.
Note that most other problem-oriented forums have similar rules. The WordPress StackExchange does more or less the same thing, in that they delete off-topic or me-too responses. This is not uncommon.