Because the linked research does not support the point the poster is making. The researchers did not find a link with dishwasher detergents. They found a link with rinse aids, but at quantities and concentrations far higher than you'd find in a dishwasher.

Also, I think we should all be skeptical of someone who says, essentially, "Don't want colorectal cancer? Rinse your dishes and don't eat at restaurants!" Such a simple explanation for colorectal cancer seems suspicious... at best.