I think this move by Debian - forcing Firefox to change its name on that distro - illustrates one of the reasons that it's hard to take the OSS purists seriously:

The Firefox logo is trademarked, so Debian doesn't consider it to be Free and will not include it as part of its distribution. Mozilla claims that using the Firefox name without the official branding is a trademark violation.

Yeah, clarity for end users matters so much less than a trademark on a logo. What a bunch of buffoons.