Plato: What Greek ideas did Plato respond to?

He speculated that Feta cheese would make a better topping on Greek salads (in Greece, they're just called salads) then American cheese. He predicted the creation of the United States and thusly the discovery of American cheese and the hideously boring invention called the Cobb salad.

According to Plato, no other Greek ideal would beat the idea of Feta cheese on their national salad. EVER!

Probably the cave.

On a broad scale, he responded to two main areas of Greek thought.

Firstly, geometry. We all know the story of how he had inscribed above the entrance to the academy, "Don't bother coming in if you haven't studied geometry" (or words to that effect!). At that time geometrical reasoning was the dominant paradigm and, if you care to read just the introductory matter and first chapter of Euclid's "Principles of Geometry", you will find that they throw an extraodinary light on Plato's discursive technique. (Euclid came later than Plato, of course, but he was essentially summarising several centuries of Greek mathematical knowledge). Like Socrates (and Euclid), Plato believed that all successful reasoning was critically dependent upon unambiguous definitions and the smallest possible number of clearly-articulated axioms.

The second major influence, obviously, was the thought of Socrates, who famously said "If I am wise, my wisdom consists in knowing that I really know nothing". What he meant, of course, is that however effectively and comprehensively we think we have explored an argument, we can never be entirely sure that we have reached "the end" - the true conclusion.

Plato responded by developing his Theory of Forms (or Ideas), which represented his best shot at supplying a definitive "theory of everything".

With regard to specific imagery and symbolism, he would of course have drawn from Greek literature and from the popular discourse of the time, but the use he made of it is, I think, of more literary than philosophical interest.

I'm sure that this is far too general a response to be useful to you, but the answer to "What Greek ideas [does] Plato respond to?" is: all of them.

Prior to Socrates, the primary concern of philosophy was pursuing a form of primitive science, ie seeking non-supernatural explanations, or causes, for events. However, these endeavors generally involved the pursuit of an "ultimate concrete reality", or state, as a substitute for god-influenced, supernatural situations.

When Socrates came on the scene, he found the tools provided for him by previous thinkers an inadequate set of tools for pursuing "reality", but a well crafted set of tools for clarifying a persons' independent (ie, natural [v. super-naturally imposed]) thoughts and directing those thoughts toward the "ultimate, concrete" state of happiness.

Plato, as a devotee of Socrates' revolutionary, philosophical goal, and as a student of a lot of prior Hellenic intellectual/cultural history, sought to syncretize those two divergent cultural strands: the "fact" and the "happy". He sought to link the "ideas" of both as coeval and to render them necessarily linked. And he succeeded...

You may have read this quote before:
"The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato" [Alfred North Whitehead]

That's a pretty impressive statement, and it has the benefit of being correct. Prior to Plato's involvement in Western philosophy, "facts" and "feelings" were regarded as independent factors. It was Plato, despite himself, that first problematized both the difference and the relationship, ie the equation, between self and cosmos.

PS: On the other hand, while i've tried to answer the posted question seriously, if your post was a passive-aggressive homosexual slur, via your examples, you've failed utterly at making a point. Trollery that tries to be clever tends to do so by parading its ignorance.