This means the "Droid" name is solely for the US under verizon, and those phones are called something else out of the US or when released unlocked or by Sprint.
And yes, it's incredibly misleading (and annoying as the Droid and the Droid Incredible have completely different UIs for instance as the Incredible uses HTC's Sense UI whereas the Droid ran a crippled stock Android system)
If you look at pages for the Droid Incredible, you'll see they also licensed the name: 'DROID is a trademark of Lucasfilm Ltd. and its related companies. Used under license.'
My guess is that Motorola didn't get any sort of exclusivity from Lucasfilm, so other companies are free to call their phones Droid as well if they pay Lucasfilm for a license - and piggyback on Motorola's marketing spend.
http://en.wikipedia.org/wiki/Motorola_droid
It also says that the HTC/Droid Incredible is on Verizon too.
http://en.wikipedia.org/wiki/Droid_Incredible
And the HTC Hero on Verzion is called the Droid Eris
Which is exactly what happened: the Droid 2 is the Droid Incredible, by HTC.
HTC wouldn't be able to come out with a Droid 2 because that's Verizon's decision. The Droid 2 is coming out later this year, made by Motorola because that's the way Verizon wants it.
Actually, Verizon did. Which is why their top mobile lines (Eris, Incredible, initial Droid) are all called Droid, the Droid is called Milestone in Europe.