If a church needs a musician to handle its music ministry(which can take a lot of time and talent)and they want a quality musician, it would be unreasonable to expect that they would not have to pay them. In many churches that is a full time job. The churches that have found good and reliable musicians are glad that they have them and are willing to pay for their service. How could one find fault in that?
Many church musicians are good Christians, some are not but are good and decent church musicians. Some are not good and decent at all but are good at their trade. Some are good Christians but not so good musicians. Some are not good for anything. Churches simply have to choose as best they can. To look at a musician that you don't know, or even one that you do know and say that gospel musicians are not musicians is ridiculous and lingering in the area of stupidity.
Why didn't the salesman just slap the customer in the face? I see no difference.
Churches have to choose what their music ministry will be like. We go to churches as suits our choice of worship. Musicians as a rule, give their churches what they ask for.
If there is something wrong with the style or secular quality of the music service in a given church, it is most likely not the musician's fault. The pastor, deacons, elders and other church officials set that tone. The musician just complies. It would be just as easy to find a musician who played hymns or smooth contemporary music.
They are all musicians.
The salesman should have been aware of that.