BS. Who forced you to do anything but show up to work? If you are seriously distracted by a rainbow flag to the point that it's a problem for you, you might have some personal issues to work on.

It's meant to tell a historically discriminated-against community that they're welcome here. I'm not sure why that would be an issue for anyone. You aren't a victim. Just relax. It's more fun on our side of the tolerance argument, I promise you.