It's like going into a restaurant and asking for a menu, only for the server to respond with "we don't even need menus, you can order whatever you like!"
"What would you like to eat today?"
"A bacon cheeseburger with cheddar, with lettuce, ketchup, and onions. Fries on the side."
"Sorry we don't offer fries with our burgers. What could I get you instead?"
"I see french fries at the next table!"
"Oh, you asked for fries, not french fries. Sure, we can do french fries. What would you like for your side?"
"... I want french fries."
...
It's not actually true that any input is accepted. Pretending that it is just creates frustration.