All of this flag flying would be perfectly innocent if there was any sort of popular tradition of having a flag up outside your house in the UK. But there isn't. Maybe there's one eccentric old dear in your village who has always done it, and still her Charles and Di plates arranged in her dresser, but that's about it.
In some countries, everyone seems to have a flag. The US, obviously. And a lot of houses in the Netherlands have flagpoles; the tricolour flag most days, an orange pennant added on royal birthdays. And even Norway, the least jingoistic country in the world, has a load of flags on display.
But it is not a British tradition to have the national (UK or English) flag flying on or outside your house. Go back to the 1950s as that nice Mr Farage and his ilk would apparently like you to imagine doing, and see if you can find a Union Jack, let alone a cross of St George, in a picture of a residential neighbourhood (other than maybe on the bunting at a street party). I suspect this is probably because nobody needed to fly the flag to feel superior to everyone else ("after all, we're British, all that flag-waving nationalism stuff is for those hot-headed foreign johnnies"), but whatever.
To fly an St George flag right now, unless perhaps you are on the way to the stadium for the rugby, is a statement, and the statement is, essentially, "Brown people can all fuck off, especially Muslims".
Now I suppose it's juuuust possible that perhaps one or two of the people earlier in the thread who asked, all innocent-like, "Who could possibly object to a flag?", were actually doing that innocently. But if by any chance you are in that position, then please, take a hint and take the flag down, because the knuckle-draggers are going to think that you're a kindred spirit, and the rest of us are going to think that you are a bit of a c not a very nice person. Yes, it's sad that the flag has been hijacked by the racists, and maybe this will swing back at some point (I can remember a time when the Union Jack was mostly captured by the National Front, but since the London Olympics it's had quite a comeback), but for now, we have this useful tool for identifying morons.
(And in any case the rightful patron saint of England is Saint Edmund, who actually was English, unlike the usurper Saint George who never came near the place. Edmund's flag has a dragon on it, which is not only ironic but also much harder to draw on a mini-roundabout.)