If you think we have open cockpits you've really no idea of our way of flying. No surprise.
As for the weight issues, I don't have any as I generally fly alone, though not out of choice...
Yes, with two people of 90 or more kgs, the typical two-seat 80 hp-Rotax-powered microlight would have a legal problem, yes. But one sees remarkably few such heavy-weights around our fields. Perhaps we keep in good trim by doing our own maintenance?