They claim you have a right to navigate any river for free. They don't claim that nobody can charge you for getting on the river.
Is it such a hard distinction to understand? You can perceive it as a charge for navigation if you like, but it doesn't take that much mental effort to see that that's not what it is.
But as someone else pointed out, rules based on that distinction are difficult to enforce. You might say that's CT's problem. But in the real world, as opposed to paddler paradise, some amount of give and take is always going to be necessary.Yes, it's totally reasonable for them to charge a facility fee for all the extra stuff they do. But the problem is if you say, "I don't want the facilities, so I don't want to pay" it causes an issue.
CT is a business and needs to make money, or at least to supplement its grant adequately if it receives one. People seem to be forgetting that. A lot of the money made by the cafe will be from walkers, or people accompanying paddlers and rafters but not getting on the water.And If you charge for access to the river via their land, then that's fine, but you can't just charge paddlers and not walkers.
I don't envisage many walkers paying to take their dogs along the Tryweryn when thousands of acres of Snowdonia are accessible to them for free.
Also, I think charging walkers would give the facility a bit of a "prison camp" feel.
I wonder what proportion of the complaints about CT's charges are really based on issues of principle, and what proportion are due to paddlers simply being tight-wads!