Armchair critics......
Oh FFS. Do you criticise aerobatic pilots for doing dangerous cunning stunts? Do you criticise horse riders for taking part in the most dangerous of sports? Do you criticise cyclists for cycling on main roads with busy traffic?
Yes, there is perceived risk in pretty much anything these days, but just because you wouldn't do it, doesn't mean it is not safe, and no reason for you to character assassinate anyone else who does. You have no idea of the skill level or experience of the pilot, or of what they are trying to,achieve.
BTW it is common practice in bush flying for washing sand off the tyres.