This is over-reach from HMRC (UK tax authorities) IMO. Only applies to sale value < £135 though. Issue is that VAT (sales tax) is now being collected at the point of sale rather than at the point of importation, which every other country in the world does. Many retailers are understandably upset by this, it's the first UK consumers have heard of it, so I suspect it will be reversed soon. Dumb-ass politicians, and greedy tax authorities who had to 'have a go'. Looks like UK residents will be paying a helluva lot more VAT in the future...
https://www.bbc.co.uk/news/business-55530721
Interestingly, ebay and Amazon.com have been 'pre-collecting' VAT for some time for UK orders, but I didn't know it was 'the law', and it didn't always happen.