By eliminating "stick lightening", MCAS makes inadvertent stalls less likely as required by certification regulations.
As I said above, MCAS is not a stall prevention device since the pilot can still stall the airplane with MCAS in operation.
LOL. Are you listening to yourself? It is like saying that collision avoidance system on my Subaru (that brakes automatically if I'm heading for an obstacle) is not really a collision avoidance system because I still can make a collision while driving this vehicle. Even when the system is activated.
Your statement does not make much sense.
The keyword here is inadvertent. Obviously MCAS won't work against deliberate attempt to stall, same as my CAS won't work against deliberate attempt to crash a vehicle. But that does not change the purpose of the system. If you deny that, you have to admit that MCAS serves no purpose whatsoever.
Let's keep the discussion to airplanes since that's the case at hand.
First we need at definition of stall.
At low angles of attack, the lift developed by an airfoil or wing will increase with an increase in angle of attack. However, there is a maximum angle of attack after which the lift will decrease instead of increase with increasing angle of attack.
The maximum angle of attack mentioned above is often referred to as the "Critical AoA". Let's use this short hand for this discussion.
Now let's describe various airplanes and discuss if they have stall prevention systems.
BAC 1-11 - The BAC 1-11 has a stick pusher. After a deep stall in flight test that caused a crash, production airplanes incorporated a stick pusher that prevented the airplane from reaching the "Critical AoA". Since "Critical AoA" can't be reached, the BAC 1-11 has a stall prevention system.
A320 - In "Normal" mode, the A320 flight control system limits AoA values to below "Critical AoA". Since "Critical AoA" can't be reached in "Normal" mode, the A320 has a stall prevention system.
777 - In "Normal" mode, as the airplane approaches stall warning, the flight control system increases column forces from 40-50lbs to over 100lbs to discourage the pilot from further AoA increases. The pilot can pull through this force increase and reach "Critical AoA" in all flight control modes. Because "Critical AoA" can be reached, the 777 does not have a stall protection system.
737 MAX - Above normal operating AoA's, MCAS activates to require increasing column forces for increasing AoA's. The pilot can pull through the increased forces to reach "Critical AoA". The 737 MAX does not have a stall protection system.