(the "moz" in DMOZ comes from mozilla through its original domain: Directory.MOZilla.org)
It's the same with Mojang's "Scrolls" vs Bethesda's "Elder Scrolls". It's silly, but because they're both in the video game category, it was a problem. If someone sold a product named "Scrolls" that was a gummy candy that looked like a scroll, it would probably be fine.
The law is unfortunate either way.
The unfortunate situation is that due to small size of Doz, the cost of litigation will be prohibitive for Doz otherwise SEOMoz vs SEODoz will be a good point in litigation.
What disappoints me most is a companies that as a startup expect to be treated nicely by larger ones, start to behave similar to larger one when they become large themselves.