Can kites be towed aloft, yes. Will riders be occasionally injured, sometimes severely, YES again. If you are very moderate in tow height and line tensions you MAY not have accidents or incidents as you have reported.
The gear is still greatly under designed in terms of strength, factor of safety, safety gear, etc. Others have not shown your restaint and have been kicked badly for their experimentation.
I have been boat and truck tow hang gliding for almost ten years. Many out there have been doing it a lot longer than that. To tow up properly there is a lot of safety gear, training, proper harnessing that just doesn't exist in kiteboarding today. Things like reserve parachutes, ballistic and otherwise, weak tow links, adjustable line/break pressure on the winch to control tension and ascent rate, a proper harness, helmets, PFDs, hook knives, proper high strength purpose designed towlines, custom configured towboats and more.
Currently we are grappling with irresponsible rider issues threatening kiteboarding access on beaches at widespread locations around the world. So, you mean to tell me that the same riders that refuse to stay away from bathers and the beach are going to stay at safe altitudes, tow tensions and far enough offshore to avoid threatening others. This in the absence of any training, safety conventions or guidance. That among other reasons is why I say it is not responsible to promote this sport.
Please get one kite manufacturer to state in writing that their kite gear is suitable for towing. Failing that, enjoy your towing, stay safe, but please don't encourage others to pursue this high risk, ill advised activity. It is equivalent to saying it is ok to pop jumps within 30 ft. upwind of a crowded beach in gusty onshore conditions. Do people get away with it, yes, will it result in injuries and losses to this sport, inevitably. Also, kite towing looks like an excellent opportunity for the civil aviation authorities to jump in and regulate after some flyers drift into some powerlines, traffic, buildings, beachgoers, etc. You get the idea.