I'm not encouraging anything. I am saying it's not as simple as "avoid this." Do you think anyone aside those that live on the boats would use these routes if there were good alternatives? Did you even look at the map? At least three serious injuries I saw on the A10 last year on the bit parallel to the towpath. Hackney council are consulting on closing rat running routes on parts of the CS1, in part because of the increase in traffic and the concomitant increase in collisions.
All I am saying is that you have to weigh the options. It may be safer to use the road, but then you increase your risk of injury from motor vehicles. Or it may not be. And please don't tell me that "they are perfectly safe, I have used them" because you are then inadvertently saying the people who have been injured on these routes were doing something wrong. They most likely weren't. And it doesn't sound like the people who have been mugged have been injured usually. Getting hit by a car risks that and getting the bike destroyed anyway.
At the end of the day the towpath is not a suitable route anyway because it's narrow, badly surfaced, etc, and Hackney and Haringey really need to provide safe infrastructure on the A10.