Stu,

You are correct.

Admittedly, Sharp's interested were very focused rather than broad.

He collected only those items which he considered worthy of collection.

Conversely, items which he did not attempt to collect were obviously those he considered unworthy.

Now, Sharp's personal preferences are not a problem.

Nor are the value judgments behind his choices, which he freely expresses.

However, there might be a problem when those values and judgments influence others.

If the English "folk" movement took its cue from Sharp and looked at folk music in a narrow and exclusionary way, that might not have been the best thing that could have happened.