There is no penalty for such time wasting in the UK.
Anyone indulging in such childish behaviour should simply be identified.
Clearly comparing people group booking vaccination slots to ISIS is taking it too far, a better comparison would probably be the waste of oxygen campaigners intentionally blocking ambulances on the roads.
What surprises me is that someone would look at a comment like that and, rather than agree with the sentiment that people who are group booking vaccination slots are c*nts and probably contributing to more people dying (as those most at risk from COVID will on, average, be older and less likely to persist with internet bookings) they instead criticise the, admittedly, OTT analogy.
There is also a world of difference between someone who makes a booking and doesn’t cancel it (assuming that they had the option to cancel it) and someone who blocks books vaccination slots to prevent others from accessing potentially life saving treatment (ironically under the guise of being pro-freedom) - one is being a selfish twat, the other is contributing to a higher rate of serious illness and harm, either by being of malicious mind, being a fucking idiot blindly following someone of malicious mind and, probably rarely (and these are the ones I have sympathy for) being picked out to be vulnerable/easily persuaded by those of malicious mind and being essentially groomed as part of the group.
It’s absolute shithouse behaviour in its purest form and it needs calling out, rather than criticising the manner of how it’s being called out.