Personally, I take the view that anyone going abroad just for a holiday in the current circumstances of rapidly emerging variants, a not fantastically competent government, and a lottery in of restrictions upon their return is a magic mix of selfish and idiotic.
I enjoy holidays in Greece, or Portugal, or Italy as much as anyone in else, but the idea that it's not really a holiday of you stay in the UK is a stupid one - if you can't have a beach holiday in Dorset, or Cornwall, or Pembrokeshire, or a walking holiday in the Dales, Lakes, Galloway in or Snowdonia, or a city holiday in Edinburgh, or Manchester, Bristol or Norwich then there's (to be blunt) something wrong with you, not anything lacking in the astonishingly beautiful and varied country in which we live.
For me, potentially exposing yourself to new variants and then bringing in them back is as selfish and harmful to others - and should be as socially unacceptable - as drink-driving.
The risks to the traveller of local lockdown, illness, and restrictions upon return are the same as those as those involved in going swimming, at night, off the coast of South Africa, dressed as a seal: the the richly deserved wages of stupidity.
(Anyone who goes on holiday to Dubai should be shot, entirely regardless of whether there's a pandemic on...).