Hmmm, I don't see why the band would have to apologise - or even try to postpone these gigs again.
Given the circumstances, planning any sort of trip abroad was always risky, especially at this time of year. Sure, many people from the continent travel to the UK for these shows, I have been on many a roadtrip to see bands in the UK myself, but I don't think I woud have taken this risk.
Also, as has been mentioned, many fans from the UK normally come over to see the band in Amsterdam and Cologne which now won't be possible. Well, Amsterdam, anyway, Cologne...that remains to be seen. Guess everyone is super disappointed - but this is really beyond anyone's control.