It is wrong, short-sighted and poor marketing/customer care for any business to treat potential customers in an off-hand way...
but...
the folk hanging around at flying clubs and schools don't necessarily have a vested interest in being welcoming (apart from common decency, which is in short supply these days) and 90% of folk who turn up at a GA airfield un-announced are spotters, tyre kickers and general Walter Mitty characters.
GA doesn't fit in with the high profile pilot image that is thrust upon you
as a child
That is indeed true - but the mistake is confusing your local club on a farm strip or crumbling WWII airfield with that image in the first place.