It's who they are and what they do.
What they are doing is aimed at the UK and is fuelled by jealousy and the humiliation of their own disastrous effort.
You'll notice they are banning the UK from receiving doses of the Oxford vaccine developed in the UK and distributed by AZ, a British company with whom the UK wrote a contract three months before the EU.
Their position is rather weak.
We may respond by reducing their supply of fatty molecules. They need it. We manufacture it. I guess we'll do reciprocity. Dose for dose. What's good for the goose...
Fortunately, the UK has a massive amount of vaccine manufacturing onshore. So they can really only slow things down a little bit.