> You can just accept that people may use the term "blockclock" to talk about block clocks.

That doesn't work if an adversarial company files the trademark instead. An evil version of Djuri could have taken down Coinkite's Github and hosting that way. If he had trademarked BTCClock and there no Blockclock trademark already.

The only defense against such an attack is already having a trademark, because that is the only way you're going to quickly and successfully appeal a takedown. 

 That's not how trademarks work.

Previously having used a conflicting trademark is a defense. There's a long list of examples of big companies trying to use their trademarks against pre-existing users and failing. 

 I think you're talking about how they work in the court system. Unfortunately much of the world is run by the kangaroo courts of Google, Apple, Microsoft and Amazon which have very different rules.

E.g. on the topic copyright, having obviously written a book yourself is not enough evidence to get it listed. Once their black box system flags something, you're fucked unless you take them to court or unless you can give them the piece of paper they want.
https://sprovoost.nl/2022/06/01/amazon-and-the-dystopian-future-of-book-censorship/ 

 None of this is relevant to Coinkite, who is a hardware manufacturer that ships their products themselves.