Theymos didn't mention such kinda rule that you have to put reference link for providing feedback. I don't think theymos will do it in future.
On feedback pages, you can leave trade feedback. There are no rules for this,
However, there are some guidelines but those are not specific rules.
Trust system is not moderated unless someone extremly abuses the system, therefore, anyone can leave a feedback. For example, I got a negative feedback from a stupid without a single reason.
By the way, I do strongly believe that there are a bunches of thread regarding this issue. You should check those before creating a new thread so that you could get the output without creating a thread.
#Edit
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I request you to read OP and about trust system.