I'm pretty sure Lego gets alot
of stupid complaints, so I don't see why they'd heed to that one in particular. Unless there was an overwhelming amount of people on board with it, I don't think it would have any effect. I can see this being a valid theory if the theme was cancelled in the first year, but after three years? Looks like it just ran out like every other theme. It's kind of like saying that they cancelled the Adventurers theme because of the mummies. Or Power Miners because of the rock monsters.
Sure, it's possible. It's also possible to win the lottery, survive a lighting strike, and be hit by a meteorite in the same day.