Bob Davenport, Shirley Collins,Isabel Sutherland,John Brune, Reg Hall,Myself the list is growing of people that either had some difficulty with Ewan or Ewan had some difficulty with.
it is very simple if a person walks up to somebody and asks politely to buy an LP, The courteous thing is to say thankyou, accept the money and say I hope you enjoy the recording, possibly offer to sign the album, it is not criticise the choice of the recording and say "you like that sort of thing do you" in a denigrating sneering voice, particularly if it was a recording of his wife and brother in law, he said it in an arroogant and patronising voice, a similiar but more exaggerated tone of voice that he used to in the radio programme to criticise Luke Kelly.
At that time I went to folk clubs to listen to international folk music, socialise and enjoy myself,I did not go be criticised for buying an LP.
I have respect for him as a song writer and performer I think he was generous with his time, but to quote your understatement he was not a diplomat.