There’s a difference between being concerned about a little cultural erasure and the idea that Christians en masse would choose Starbucks as the hill to die on over that issue.
Of course, this is a lot more believable nowadays since we deal exclusively in caricatures but as I said earlier, it was novel at the time.
So, no, none of this was novel to me in 2015... you seem to be reading in the "en masse" part yourself. A substantial number of people believe in this War on Christmas stuff and do let it influence their behavior, including the 2015 cups. You seem to only be willing to accept that it's either just 1 person, or EVERYBODY.
I can show you more links if you want, but so far you're not even trying to consider the counter-evidence people have posted here... if you were actually curious, it's easy to Google. But - ironically, considering the claims of your original post - your mind seems made up.
Of course, this is a lot more believable nowadays since we deal exclusively in caricatures but as I said earlier, it was novel at the time.