“Do something” does not have to equate to spraying.
But doing something is better than nothing. Nothing can quickly lead to the deleterious effects of too much vegetation, which is much more than just navigation. Diminishing beneficial bacteria that eat the natural muck that comes with eutrophication is one thing. Reduced dissolved oxygen is another thing. In many bodies of water with outlets to a river system or chain of lakes, vegetation can (and does) block natural water movement which can lead to flooding, which further alters water chemistry (of the lake as well as the river outlet).
We have the knowledge to “do something” for our waterways that literally benefits everybody but the chemical companies, and we won’t do it. “Do something” to me, should be calling for physical removal to be the first and best choice for managing vegetation in our waterways.