I agree, this is quite a situation!    I was unaware of it.  I am totally with you…as I carry my own whenever possible. This all stinks, as I have been going to food coops since the 70s w/o problems with my own containers. But lets discuss the issue from "their" (WF) point of view to understand it better.

A. I wonder if stores are getting stricter due to Salmonella outbreaks, and other recent health issues.  They don't want to be sued and there are a number of ways they could open themselves up for that.   I can imagine they will create a mandated store policy not to allow this "cross contamination" (thats what its called in food sanitation terms) as the issue gets more well known and public. 

The question is then, what can we all do to enact change?  Perhaps the change will have to be in baby steps, or settling for WF dispensing folding biodegradable paper containers…made waterproof by a natural, non plastic substance. We NEED to make it public loud and clear though…regardless of why they won't allow it, they have a DUTY to figure it out because they call themselves "a green company," right?

B. I think they also do not want to be dealing with broken glass (it happens in grocery stores…I once worked in one) , and to sterilize containers "on site" would take thousands of dollars in retrofitting.  Maybe hundreds of thousands.  At least with Oberweiss the glass bottles are collected somewhere and taken away to the plant that will sterilize them. They are uniform in size, and big/heavy enough to not break.  Smaller bulk food containers would be much more difficult to stack, package, and where would they go to be sterilized?

At the least, and safest, paper containers might be an alternate solution, should it become mandated by law everywhere NOT to allow bringing one's own containers into a store.  Why aren't biodegradable waterproof coatings being made for paper and cardboard packaging?  Because the research funding is always in creating new and different plastics. Sad.