The Guardian is an extremely biased source. They even refused, multiple times, to run an Op-Ed from the creators.
https://deadline.com/2020/05/planet-of-the-humans-pulled-you...
https://deadline.com/2020/05/planet-of-the-humans-pulled-you...
It doesn't seem crystal clear at a glance whether the copyright complaint is well founded, or if it's fair-use, but I don't see that it matters much either way. Spinning it as 'blatant censorship' seems pretty silly.
Even discounting this, and the Guardian article, Wikipedia lists a number of serious issues with the film.