It's just distrust of the unknown. Some people like to try new things, others are afraid of trying new things, in case they don't like them.
For example, when I was in college I made a pot of Spaghetti Bolognese for myself and my girlfriend. As I had made more than we needed, I offered a plate to a friend who happened to be there, at the time. He refused, as he had never eaten it before and didn't like the look of pasta. I was speechless. The idea of a penniless student refusing a free plate of spag bol...
It's worse with beer. The big boys spend a fortune on advertising, to make people think of their beers as friendly, accessible beverages, that everyone enjoys. That's why people think of micro-brews as foreign. What they actually mean is unfamiliar, because in order of a beer to be considered safe and familiar, you must have been exposed to thousands of reassuring adverts for it.