It is just not true that all airlines have 100% competent people or that they always have 100% committed people either. If you believe that airline owned maintenance organisations never make mistakes just read through the top 50 accident reports which cite maintenance error as a causal factor.
I accept that MRO's are no more immune to error than airline maintenance arms are either. It is just plain wrong and short sighted to condemn all MRO people while painting all airline staff as saints.
When you have spent as many years in both [as some PPRuNe contributors have] then you may have a more balanced view.
Most bias against Independent MRO's is rooted in the fear that they exist to takeover the work of airline maintainers.
The airlines only outsource work where:-
a] They get good safe products and,
b] Where it is economic to do so.
Look at the record of some European operators who:-
a] Do not have a base maintenance capability and,
b] Have had no accident in 20 years.
I wholly recognise the esprit which exists in airlines where flight, cabin, maintainers and management work together as a team. I know as I experienced it for 24 years, but I am not able to say I found standards within large MRO's in any way lacking in comparison with airlines.