This is one of the issues that I have trouble making a solid decision on. I am all about personal property rights. If I have a business and don't want to deal with folks that say.. wear two left shoes on a regular basis, I think I should have that right. It is after all MY business and MY property and I don't like the idea of Joe Public telling me what I do with MY stuff. BUT... what I just described is blatent discrimination. Bad thing? Depends on what is socially acceptable at the time. At this time in history, property rights are not as important and ensuring that everyone gets fair and equal treatment is.
Now the sad thing about the Google example is that it isn't a popular issue. Discriminating against gun owners/retailers isn't a cause that is likely to stir up much except for among us poor gun owners. Now if it were a minority owned business, then it would have teeth.
Ian