They reject ideas that won’t work
As a leader, one of your functions is to protect the organization from bad ideas. Make the distinction between idea and innovation – innovation happens when an idea is implemented, its assumptions are tested, and lessons are learned.
If the idea can’t be implemented in its current form, it can nonetheless be an input for future creative thinking. That creative thinking could come from others, or from the person who proposed the original idea after new experiences and the passage of time.
It would be very rare for anyone to pitch an idea fully formed and ready for implementation. Most ideas are built from multiple inspirations and sources.
If you reject half baked ideas, pretty soon the pantry will be empty.