The policy still allows criticism of people, just not in everyday discussion - which is correct, because it doesn't belong there. A person can be criticized (i.e. critically evaluated) by their manager, or perhaps by the person's peers privately telling their manager.

But "criticize the idea, not the person" is a ground rule of any healthy intellectual culture. Criticizing people in a discussion about ideas immediately shits up the atmosphere. It's uncivilized.

If someone consistently generates poor ideas, figure out some way to tell them respectfully after the fact or get their manager to do it. Either the person needs to fix their process somehow or they're not suitable for the environment. These both sound like things a manager should be judging because they are.