In this case, they're probably making things worse for themselves overall, but I wish people would take the complexities of trademark law in account before accusing them of censorship.
I wish people would not try to justify corporate bullying based on a misunderstanding of trademark law.
Also: it's legal counsel, not legal council.
> Complaints regarding trademark infringement due to website content and domain names are outside of ICANN's scope and authority.
The only case where ICANN Has anything to say is in a case of domain squatting, which this isn't: although Canonical has a trademark interest in "Ubuntu", there's no violation since it's being used nominatively,and it's not being used in bad faith. (Search for UDRP for more information on this policy).
(BTW, copyright and trademarks are very different things, be careful with your terminology.)
You're right that copyright and trademark law are two different things. That said, the word "trademark" occurs on that page only in the footer, applied to the name Debian. Nowhere (on that page at least) are the images asserted as trademarks, whereas there's a prominent copyright notice near each logo. I suppose the copyright could be read to apply to the license text and not to the logo, although that would be odd, and inconsistent with the explicit copyright wording of the open use logo.