Going past moored boats make it harder, because they narrow the channel and you have to slow down for them, and on bends it is even harder. Occasionally it's nice to see a moored boat and not be alone.
But when it's a long, long line of moored boats,
and the boat on the move is crawling all the time,
and the other boats haven't tied up properly
and their lines are loose,
and they are scowling out of the window at you because their idea of slow is different from the passing boater,
and the boat on the move can't find a mooring himself because there are too many moored,
and the towpath is tatty with their rubbish because they have no room on their boat,
then, yes, it can life harder and it is everyone's business.