Re: A fork is not a cleanroom implementation
> anyone can make a copy of any copyrighted work
No, not *any* copyrighted work; this is about a piece of work that was released under a specific licence, one of many licences that grants anyone the right to make a fork - explicitly *not* a clean room implementation, but a fork.
> then claim that the rights asserted by the original copyright holder don't apply.
The licence chosen explicitly describes how extra clauses may be added by the originator and, importantly, may be removed in the fork - follow the link in the article, read starting at line 348, paying attention to line 359 onwards.
> How on earth they decided to mix in trademark violations in what was an otherwise open-and-shut license dispute is beyond me.
Precisely how that fork can be used, including but not limited to how it can be distributed, is controlled by the particulars of the original licence; for example, you may not have a grant to use the trademarked name of the original to describe your fork. Such restrictions are commonplace, and quite reasonable, but not automatic - there is pretty much a standard way of writing them.
In this case, the main licence explicitly allowed for the addition of restriction of trademarks clauses (line 384) BUT the actual additional clause didn't bother to do that!
I'd be willing to bet that it was added to the claim because it is a commonplace condition and they may have thought it was automatic: usually, even if you are allowed to make a copy (e.g. patents have expired) you aren't allowed to say that "this *is* a Dyson but we've changed the plug" (you can make comparisons to a Dyson, and acknowledge their trademark).