Do you have a reference for this? It has the sound of an urban myth. CAMRA has been encouraging breweries for some time to produce some beers without using isinglass to clear the beer for the the benefit of vegans/strict vegetarians but not all beers. I don't recollect CAMRA making any stipulations about the food in pubs. To quote from the CAMRA Pub of the Year Competition, "Pubs in the competition are selected by CAMRA volunteers and judged on their atmosphere, decor, welcome, service, community focus and most importantly – quality of beer" - no mention of food.