Communication must be two-way to be useful. If you disallow criticism, so that only agreement is allowed, the communication ceases to be interactive. You lose the ability to discuss an idea before accepting or rejecting it.

I agree. "Criticizing or shutting out other people’s views is forbidden" may make sense at Thanksgiving dinner, but it's a very odd rule for a discussion group. Swimmer963, do you think there was any benefit to this rule? Because my reaction to this situation would be either to criticize the rule or privately roll my eyes and resolve to not come back.