You can fly, as long as you have "a legally permitted reason to do so." A holiday is not a legally permitted reason (as of Feb 15). A common legally permitted reason would be business travel. Ryanair doesn't know whether you have a legally permitted reason to fly, or whether those rules will still apply on the dates of your flight, so they're operating as if you have or they won't. Basically, their attitude is hang on for grim death to every last penny and only give it up with bad grace after one hell of a fight.
Last year we had to resort to a credit card chargeback to get money back for a flight they cancelled.