We've all been there; local eateries do carry normally only a selection of local beers. If your preference is not available, they offer to get it for you - which I find perfect and very customer-friendly.
I - for one - do not know anybody who would not be happy with this customer-oriented attitude and certainly the diner(s) will gladly wait for their drink of preference to arrive.
Me thinks, that there is a flip side of the coin, lost in translation. Alternatively yet just another example where this Farang-bashing, taking place all over Thailands upcountry provinces - by default, education and ministerial point of view, has sank in. If Somchai is being told over and over and over again, that Farang are dirty, are rich and are an non-caring bunch of people which are tolerated in Thailand only for their money, it will eventually sink in over time.
As said, there is a flip-side of the coin; I cannot see a couple of foreigners going over the moon while waiting for some staff getting their preferred tipple next door.