You don't have to produce/extract/manufacture anything to make the ocean hold uranium for us.

You don't have to build anything to make uranium radiate.

That's a pointless argument and unrelated to "renewable", which means it won't get used up.

the solar panels and wires and plastic that hook these systems up to the grid/end-user require a lot of producing/extracting/manufacturing

Why is that an important difference? To capture wind and solar you have to build turbines and solar panels which aren't free. You also have to have batteries to store them because of seasonal nature of these sources. You also need to transmit the energy thousands of miles through electrical grid because these sources of energy are limited to certain areas. Building the electrical grid itself just needs cutting out millions of more trees. So overall, the environmental impact of going full solar/wind would be worse than a combination of solar, wind, nuclear, and even maybe natural gas.

We need tons of coal and plastics to capture the sun shine.