Oomis,
L’kula, is the minimum standard of halachic chiuyv. it IS the halacha that Hashem gave us. He also gave rabbonim the power to pasken, and they often pasken far more than is required by the perfect halacha that we were already given. we make a choice to be more strict, or follow the given halacha. Kula is not a four-letter word (except as I spelled it). And the people who look at it almost derisively, err seriously. following the kula is NOT the same precise thing as saying someone is more mekeil, because being mekeil sometimes involves letting something “slide” to a certain extent (like when a rov paskens that something is “kosher” b’dieved, but really it should not be used). A kula means that the item was never a chashash in its kashrus. Just some people hold more strictly for themselves.
In my earlier post, I expressed (albeit in a long-winded way) why I (respectfully) disagree with you.
http://www.theyeshivaworld.com/coffeeroom/topic/kosher-subway/page/5?replies=209#post-207086