As for the bull- bulls are associated with red for multiple reasons ( https://en.m.wikipedia.org/wiki/Muleta in bullfighting, Red Bull caffeinated drink, color of Bulls NBA team jerseys). System76 marketing: “No bull. ...Is it charging? It's charging. Must be all the AMD red. Time to run. No, bull!”
The "democrat" party (actually Democratic, using "democrat" is a Republican party slur) in the US is conventionally blue and the Republican party is conventionally red.
Red has also been used for "workers" parties and organizations, like the UK Labour party and various socialist and communist parties.
I'm pretty sure that the choice of red by System76 has nothing to do with politics.
It unintentionally may attract various political party fans, as well as other fans of the color red.
Coincidentally, China is associated with the color red, and AMD was forced out of China in 2019 for having a relationship that was too close: https://www.wsj.com/articles/u-s-tried-to-stop-china-acquiri... https://en.m.wikipedia.org/wiki/AMD–Chinese_joint_venture
But, team green and team blue have China links as well. For example: https://www.nytimes.com/2020/11/22/technology/china-intel-nv... And also possibly relevant (x86): https://en.m.wikipedia.org/wiki/Zhaoxin
As for the bull- bulls are associated with red for multiple reasons ( https://en.m.wikipedia.org/wiki/Muleta in bullfighting, Red Bull caffeinated drink, color of Bulls NBA team jerseys). System76 marketing: “No bull. ...Is it charging? It's charging. Must be all the AMD red. Time to run. No, bull!”