Roud, when discussing glees comments that they "were on their way down the social scale , and the were eventually found in the villages and town acverns and even on the streets of London" and quotes Alfred Williams' Folk Songs of the Upper Thames:

Glees were usually sung my those having slightly superior taste in music; that is, by those of above average intelligence among the villagers, or by such as had been trained at some time or other to play and instrument, it may have been a fiddle or cornet in the local bands, or in the choir on Sundays in church.

(If one of the collectors born into the middle classes had said that would they have been criticised for being condescending?)