Yeah... I've had that too, some people even comparing bonsai with Chinese foot-binding.
The same people that let plants die a slow death in their homes, force their trees to form espaliers, cut down their roses, clip branches and twigs to create topiary, and basically use the same techniques as we do - just on a different scale. I never quite understood their problem.
I don't like these 'tortured trees' but I guess the fact that I react is proof that this is art, as art is supposed to evoke a discussion... but the artist's conclusion
"Today what we feel and know as Nature has become something artificial, technical, and sociological. Men are fabricating an artificial world of their own according to their personal interests"
is nonsense if he relates that to bonsai (which apparently he does) as Bonsai is not a modern invention, but an ancient art.