What's their beef?

I am 100% behind the idea that supermarkets and butchers should not stock meat from areas where deforestation has been used to create grazing land. I see that Tesco in particular has come under attack from Greenpeace on this score but I think the story is more complex and nuanced than the press headlines suggest. Tesco may be the wrong target as they have already stopped buying Brazilian beef (the most problematic source) and their two meat suppliers, Moy Park and Tulip, already meet the supermarket's zero deforestation standards.