Perceived quality and the emotional response to a brand name is everywhere. Companies spend millions each year to support these images. It effects many things in your life. The clothes you wear, the car you drive, store brand toilet paper, or name brand. You might not even notice it. Brand name is so important that some companies buy old brand names in hopes of assuming their reputation, rather than spend many years building their own. Here's a little story about a fake but average American bicycle brand.
Brand X was established in 1890. They sold a million bikes by 1905. The built up a good reputation for quality which helped them survive the great depression. In the 70's people wanted a different kind of bike. In order to make these new models competitively priced cheap components were used. Cheap imported bikes started to flood the market, once again quality took a hit to keep prices low enough to compete. In the end they went bankrupt, they were bought out and production was resumed in Asia. Do they have the same reputation for high quality as they did then? No. Are their $80 2011 model bikes as nice as the models they made in the 1930's? Probably not. That doesn't mean they aren't functional bikes. Plenty of people ride and enjoy them.
Make no mistake though "X mart" bikes represent the lower end of the quality spectrum. Someone had to build a bike, ship it half way around the world, add a small retailer markup and sell it for $80. There are single components you couldn't buy for that price. Some corners had to be cut.
As far as bikes go, this is probably the most open bicycle forum on the web. You've got people building "X mart" bikes, and people building $1200 1930's classics. I've never seen any "low end" hate, although some people may speak their minds about the quality aspect. It all comes down to opinions. Everyone has one, don't take it personally.