I'm not sure i follow the argument that introduction of information by a middleman is adding to market efficiency. Your note expressly suggests liquidity be be witheld...when trading with people who have information.

As a result, market makers try to focus on providing liquidity to people with consumption preference while avoiding (or charging higher prics to) the informed.

Only to usurp the information to benefit the market maker (or other intermediary party...fronting or not) at the expense of the person introducing information. Or, are you trying to say that person is actually 'witholding' information and by 'appropriating' it, you are then responsible for 'introducing' it?