The Yes on 8 letter made no "threat of loss of business." It said it would make public information -- who's giving to No on 8 -- public.

Well, if you want to be really pedantic, and it seems that you do, the phone call didn't overtly threaten loss of business either. From your own transcript, the key passage was:

I do plan to pull out and find out who your customers are and let them know, especially in the food service industry and the larger stores, and let them know exactly how you voted on it

... so gosh, he just wants to share some information! It looks like we only have another case of a good-spirited citizen wanting to "make public information public"!