//Have you not been reading all my posts concerning the Brexit benefits over the last few years?//
It wasn't necessary. This requirement has been widely publicised and the details are provided on all airlines' booking sites. But even now, as you pointed out this morning, there are still some people who cannot be bothered to read:
https://www.theanswerbank.co.uk/Travel/Question1837355.html
It's not a "Brexit Benefit", but what is a benefit is seeing the UK revert to being a normal (i.e. non-EU) nation.