Personally I find it a bit disingenuous singling out Luton or any airport for that matter regarding social distancing. It seems to me that after the Cummings debacle most people said sod this for a lark. In my local area SD is very hit and miss and mostly miss. Last week I decided to have a meal out for the first time since March. The restaurant in question never asked me for my name or phone number (I thought it was the law) and sit anywhere you like - it was not busy so that really did not matter that much.
Back to airport matters I would think the airport is quite pleased to get nearly half a million passengers in July in the present climate.