Who's behind this?

I very much enjoy David Gordon's  genuine concern for worship and how it is to be carried out. However, pg. 61 in, Why Johnny Can't Sing Hymns, caught my attention. He seems to imply that guitar cannot be a serious instrument. He uses an argument regarding his students using classical music and hymns for weddings and serious occasions. 1-2 years ago my sister got hitched...married. I walked my sister down the aisle to my eldest brother playing guitar. Now, needless to say he was not pulling out a Van Halen lick while she walked (maybe he secretly was). My point is, Does it not depend on the instrumentalist and how he uses that instrument to determine the seriousness of it's form? Let me clarify. Famous banjo-virtuoso Bela Fleck does not use his instrument for mere hill-billy licks. In Musicianship (courtesy of David McGrew), we had the privilege of listening to very serious- sounding classical pieces performed on the banjo. Is Mr. Fleck unwise to do such a thing? Or is it one of many ways to approach a Bach Invention? P.S.- Sorry I couldn't be there. I'm trying to get over a sinus infection!