Little children could like the move and ask their parents to see it. That could be one reason it made it past the first one.
What did they do for the 3d effects anyway? I think they used red and blue filters, right? That is just…terrible with a full color image…to actually make it look right and not screw up the colors it takes polarized filters, or shutters over each eye synchronized with the image. It just isn’t worth doing full color 3d images any other way.