It's unfortunate that many have forgotten the background to the MEL approach to life.
If any component/system relevant to the TC is U/S, then the aircraft necessarily is unairworthy as it no longer complies with the TC - a condition for the issue of the CofA. Fine philosophy but impracticable in the real world ...
The MMEL (from which the MEL is developed for the particular operator/regulator) looks at a range of reasonably expected problems and considers the reason for the U/S system in the first place. By invoking relevant restrictions, the risk levels can be kept within the certification boundaries and there is no reason why the defective ship ought not to be considered OK to fly within the published restrictions.
Company policy will dictate routine MEL application and, in general, if the maintainers can't fix it and there is an MEL permission, one should expect the MEL to be invoked.
However, the MMEL doesn't necessarily consider all relevant matters pertaining to this next flight we are contemplating. A particular MEL permission is just that .. a permission, not a direction.
As always, the folk in the sharp end are the last defence in the Reason Model .... a pity in those environments where the pilots are constrained by background pressures to accept the MEL without question ...