UK fining an American company for this is absurd. 4Chan isn't breaking any laws. You can make it illegal for your own citizens but you can't regulate a foreign business. UK citizens should fight for the right to free speech though.
How about the EU imposing GDPR restrictions on non-eu companies?
Depends on whether those businesses want to do business with the EU
I think that's different because I have a positive personal opinion of the GDPR and a negative personal opinion about what the UK is doing. Therefore the GDPR is good and this is bad. It's really quite objective.