Wrong question. Nobody is saying they should - there is nothing moral about their decision. But if a significant portion of the local consumer base finds it distasteful, there's a market for a eateries that don't serve it. I'm sure there's a broad variety of eateries that don't serve insects in Bangkok or Singapure, partly because of the demand of Western tourists and expats.
I would get it if a halal kebab shop were to open in Bristol for example. But a Western chain caving to a pressure of an aggressive and loud minority is quite another.
You persist in trotting that same claim while you have failed to support it. A private corporation makes the decision to dedicate 200 of their eating facilities out of over 1700 to serving only halal products (which automatically excludes pork products) to meet a marketing demand based on a ratio of consumers who will only purchase halal products and you jump to the conclusion that Subway is "caving to the pressure of an aggressive and loud minority". In your OP you even spoke of "Islamist pressure". Your use of the term "Islamist" reveals to which extent you do not know the difference between IslamIC and IslamIST. It is interesting to see how a choice of words will expose someone's limited knowledge.
To my knowledge, you are not part of the corporate management of Subway who made that decision. You have zero insight as to whether an "aggressive and loud minority" pressured the parties involved in that decision. Yet you pursue with the same claim as if it were an established and demonstrated fact.
If a restaurant frequented by locals that has always served insect were to change their menu to not serve insects to appease Westerners I would understand the locals being upset. And especially so if a part of the new rules that all food must be prepared by Westerners.
There is a tendency for the Left to be too tolerant of the intolerance of Muslims.
I could equally point to the tendency for the Right to fester nationalistic sentiments while they define what a "True (place whichever nationality)" ought to be. Further the tendency for the Right to reject cultural diversity while promoting cultural uniformity. It has been demonstrated in the history of mankind that such mentality has fueled political systems which engaged in the oppression of cultural minorities if not their elimination.
Be it Muslims demanding halal only in restaurants, schools or workplaces or Muslim speakers in colleges demanding audience be gender segregated the Left will tolerate nonsense they would never tolerate from Christian fundys.
I am not aware of a body of Muslims in the US representative of the Religious Right Wing as it is the case for an actual Religious Right Wing composed of Evangelical Christian organizations who are widely known to influence Christian legislators in promoting legislation and passing them which will affect an entire population.
Just like they demand Indian creation myths being taken seriously (for example Kennewick Man or sacredness of every tall hill like Mt. Graham) when they would never dream of demanding the same for Christian creation myths.
"Christian creation myths" have already found their place of fame and popularity in the US (unfortunately) via some school boards (as it is the case in Texas) imposing Intelligent Design teachings in the Science curriculum. I am not aware of "Indian creation myths" being imposed as part of Science classes in the US. What I am aware of though is the historically demonstrated reality that Native Americans (whom you refer to as "Indians") were the only legitimate indigenous population until European colonialism oppressed them and robbed them of both their land and traditions. The least Americans can do today is show some degree of recognition towards a people who tremendously suffered under European colonialism.
I also find it somewhat ironic that someone commented on how foreigners who come to their country should not impose their cultural traditions while when it comes to the nation defined as the US, it is exactly what happened during the European colonial period.
I think all religions should be treated the same and none should be allowed to control the lives of non-members.
Try to present a coherent and rationally centered argumentation demonstrating how that sentence applies to 200 out of over 1700 Subway owned eatery facilities being dedicated to serving only halal products. How are non halal product consumers of the Subway private corporation falling under the definition of their lives being controlled considering that they have over 1500 Subway owned eateries which will serve products compatible with those consumers' market demand for non halal products to include pork products?
