If you have nothing constructive to say about our project then better dont becouse let's keep this topic clean as possible.
You should be open to criticisms, constructive or not. Because you have yourself in with this type of project, you should be more open to it because they'll come eventually, and let's say it becomes a successful project, there will be more of them for sure.
It's not all about keeping the topic clean but it's better to see it mess up you're trying to maintain it professionally and answer most of those queries in a professional manner. That's why you should be prepared for it.