They are devious and duplicitous, intentionally playing Gotcha! by choosing to attack those businesses whose products or services would give a defacto credence to the lie of a homosexual "marriage". If the transactions were homo-neutral, such as in the examples you gave, who would care. I doubt they are wasting time at 7-11s to see if they'll have trouble buying Slurpees.
The purpose is not only to validate the deviancy, but to enforce the government's power to pervert the language whenever it wants, especially the time-honored words that describe sacred traditions and values, respected institutions, and cultural norms that serve to elevate and support a healthy society.
Once the word "family" was corrupted to include all manner of shack-ups, shake-ups, mix-ups, and screw-ups, there wasn't a sturdy enough foundation left to withstand the bully forces that have redefined "marriage" to include something it is not and never will be.
Now that the world of lies is hopped up on speed, those in utter rebellion to truth are on a mission to destroy those whose values are not and will not be determined/debased by "popular" culture, government edict, or any other aggressive conversion tactics employed by the dark side.
I have read comments here along the lines of, "Don't these people know that they aren't winning acceptance, so their victories are nothing but a delusion?" Oh they know all right. It is only a lawful, moral people who perceive successful change as being of open-hearted choices free of coersion and deception. The Amalekite mind, OTOH, is perfectly satisfied with power for the sake of power. These folks couldn't care less if you agree with them out of free will or with feigned words, so long as you submit to their will.