The advice of Uncle Bob should be taken with a large grain of salt. It is always important to understand the context for advice and the trade-offs involved.
Bob is a proponent of the object-oriented paradigm. The underlying premise is you want to follow the OO paradigm. If you prefer a functional style or some pragmatic middle ground, his advice might not be for you.
If I understand you correctly you prefer to test methods individually. This is much simpler if there is less reliance on object state, and more on parameters. Pure side-effect free functions are especially easy to test. But this is functional style. In OO style, the "unit" is the object, not the method. You don't test a single method in isolation, you always test the behavior of an object.
When you say methods with fewer parameters are more coupled, I assume you mean more coupled to the state of the object and other methods on the same object? This is not necessarily a bad thing in OO - rather you try to achieve low coupling between objects and high cohesion for the object.
I don't think anybody have proven one paradigm to be superior to another, so this all comes down to opinion (or religion). But if you accept the premise that you want to strive for a pure OO architecture, then the advice of Bob makes sense.