on football, flags and France

I'm not really a sports fan, but I managed to watch some of the football recently, whilst on holiday in France. So this will not be insightful commentry on the actual games, though England were dull as dishwater mostly. For the record, I'm now cheering on France, as I have Hugenot ancestors, at some point.
The point. which came to me was the huge number of flags which litter the central reservations of UK motorways, there are literally thousands of them, snapped off and flung by car wheels, to the middle, to lie poor and neglected for the remains of the summer. Oddly, in France I only saw some sun hats with French colours, alongside some shoes for Portugal, Brazil and France. Yet there is no denying that the French support their team, but their cars are unadorned. I'm puzzled as to why the English feel the need to drape their houses, cars and children in the English flag, primarly for football.