You cannot infer the Platonic ideal from existence, or at least, doing so requires justification.
There is a school of thought that holds mathematics to exist as a form of Platonic ideal.
Mathematics as god, if you like.
Here's Roger Penrose's take on this:
I have a lot of time for Penrose - I'm a huge fan, in fact. However, even in Penrose's schema, the apparent existence of a Platonic mathematical world only comes about through the mediation of the physical with the mental worlds. I would hold that we don't understand enough about the mental world and how it is generated to postulate any Platonic ideal. It's ok to say wrt certain questions 'I don't know'. Personally, I see no need to go beyond the statement 'existence is', or 'experience is', as that which we can know but cannot demonstrate - the Godel statement of the logical system that is the universe, if you like. And as Godel proved, any logical system must have such a statement. Its existence shows a lot about the nature of such systems, but doesn't really prove a god in any meaningful way - to do that would require stepping outside the system, and that's the one thing we cannot do. We can merely note the limitations of our perspective from within.
Godel himself disagreed - he was very religious. But I can only note that as a curious thing. Wittgenstein professed to be a Christian, despite all he did to show how divine knowledge is not possible. That is also a curious thing. If you wish to identify 'god' as 'existence' - the idea that existence is - that's fine. I don't see the point in that kind of reductionist definition, though. It's quite possible to live without it.
