Why do alligators and crocodiles prefer rivers/lakes to the ocean?

The saltwater crocodile native to Australia can enter the ocean, but in general alligators and crocodiles simply evolved to freshwater environments.

What I learned is that they prefer rivers and lakes because that's their habitat. They only fit in, in that area. Like if they went into the ocean they'd die and wouldn't camouflage in the oceans' water.

The saltwater would eventually kill them, but there are saltwater crocodiles.

That is their natural environment. Not equipped for the ocean.