[lorenzhs]

Gladly: Any redistribution of modified versions of Ubuntu must be approved, certified or provided by Canonical if you are going to associate it with the Trademarks. Otherwise you must remove and replace the Trademarks and will need to recompile the source code to create your own binaries.

This means that if you don't associate it with the trademarks, you have to remove and replace the trademarks AND recompile the source. Note that this covers any use of the trademarks, not just infringing ones. You gloss over that case as "just remove the trademark", but trademark law doesn't require that if the use isn't infringing. So Canonical are using copyright law to prevent non-infringing uses of their trademarks.