פירוש על עבודה זרה 68:6

The fact that it is prohibited to derive benefit from Bithynian cheese is probably what leads R. Shimon ben Lakish to posit that most of the calves there are used as sacrifices. If the issue was simply non-kosher ingredients, then it should have been prohibited to eat the cheese but permitted to derive benefit from it.

The problem with Resh Lakish’s statement is that even if only a minority of calves were slaughtered for sacrifice, the cheese would still be prohibited, for R. Meir does not follow the majority status. He is also concerned about the minority.
The answer is that if only a minority of calves were slaughtered for idolatry, we would have “two minorities” here. The second “minority” is that the cheese may be made from animals besides calves. Thus only some of the cheese is made from calves, and only a minority of calves are slaughtered for idolatry. If this were true, R. Meir would not prohibit the cheese. Therefore, Resh Lakish had to conclude that a majority of the calves were slaughtered for idolatry.