That's like saying: "The customer is always right."
I think it's a terrible idea to enable petulant behavior by saying that everybody has a right to complain.
Everyone has a right to their own opinion whether it is the basis of a complaint or fueled by frustration (at whatever), but if they express it here it does need to be kept civil and within the rules, and preferably constructive. I see a lot of worth to a thread about a missed release date if it gives people a chance to explain that this was not an official date - providing the whole thing is conducted in a civil manner.
As for this thread, it has been civil but there's really no reason for it. If there are two many threads about this issue starting a new one just adds to the initial problem, if there are too many complaints about this issue having a thread complaining about that fact just adds to the initial problem.