I'm not convinced that the artificial canals (by themselves) contribute to damage from the storm surge. The Casey person seems to conflate the issues because he doesn't like artificial canals for other reasons.
Cape Coral lowered its weirs before the storm. If the water levels in the canals were low when the storm hit, it might actually reduce damage by giving the water somewhere to go (e.g. compared to filling the canals with dirt).
Monday morning crews lowered weirs along Burnt Store Road, Gleason Parkway, and Chiquita Blvd to make more room for stormwater.
nbc-2.com
On the other hand, Captain Obvious says that packing a lot of houses on low lying land near a coast that is frequently hit by hurricanes is not a great idea.