Britain has pissed them off by not being a subservient province. I’m not going to believe that the EU isn’t seeking small ways to punish Britain where they can.
I can think of a thousand ways that the EU could make this a very unpleasant experience to travel into Europe. In this case...they get a stupid fingerprint and image (same that anyone who wants the visa to live long-term in France/Germany).
If I were the EU and really wanted to demonstrate to the UK guy my power....I’d charge some sixty Pound yearly fee for entry cost.
(Note: I’m not pro-EU, but I live under the umbrella and understand how they function.)