The visitors don't really represent anything specific.They're just based on random memories. The planet/alien doesn't understand humans any better than they understand it.
The planet Solaris is a post-Instrumentality world.All life on the planet is a single being in the form of an ocean of goo. How could one creature have evolved to become intelligent? Obviously, it didn't start with one creature. The "thinking ocean" is the result of an extreme Assimilation Plot.
The Ocean on Solaris is a technological artifactThe planet Solaris cannot exist naturally where it's located so one might conclude that it and the Ocean were placed there by some other intelligence. The Ocean is pretty weird so one has to speculate on the strangeness of its possible creators. Wonder if they're the same lot who descended on Harmont in "Roadside Picnic"?