It looks to me like the Sharp Suited Ukulele player was a symbol of the old establishment of entertainers (George Formby et al) and there was a look of hostility towards someone who was winning over the public so well. Although, it's the Kinks, so who knows?!
Crazy how it all comes round in circles. Nowadays a sharp suited Ukulele player would be going against the establishment of modern music. (ala Mr. B)