I understand not letting people in the UK register new .eu domain names. But by making it impossible (or just hard, more likely) to renew domain names imho they are needlessy hurting people and businesses who had bet on the EU.
They, in this case, being the British government performing the Brexit, not the EU enforcing the agreed-upon rules. The Brexit has consequences, be they negative or positive, that are real and can have a lot of impact on the lives of both British and EU citizens. The British government has accepted these as representatives of their voters.
After all, establishing an entity in the United Kingdom has, until now, been an equal level of 'betting' as establishing an entity anywhere else in the EU.