You are coming at this all wrong. The important question is not what Plato did and was trying to do, it is what is the truth and how can it be clearly communicated to people so they can make use of it. If Plato communicated in a way that in fact lead many of those who read him to not actually arrive at the truth, which seems to be what has happened, then it doesn't matter if he himself knew the truth and wanted people to understand it correctly.

(Oh, and by the way, the author's claim that Aristotle misunderstood Plato seems quite dubious, given that he was Plato's student for many years, and so Plato had abundant opportunities to test out his understanding and correct it if it was wrong.)

Here is a way of looking at it. Take two scenarios

1) Plato is wrong, people correctly understand him, and they are persuaded he is correct, and so live according to mistaken ideas.

2) Plato is wrong, people misinterpret him as believing ideas that are in fact true, and they themselves are persuaded of those ideas, and so live according to the truth.

Now which is the better state of affairs? Obviously the second one. So the philosophical search for truth is more important than correctly interpreting Plato. And if you are sincerely interested in finding the truth, then you should read many more philosophers than Plato, and above all try to think independently rather than slavishly following any particular philosopher.

And if after doing this you conclude that Plato's ideas are correct, what you definitely should not do is urge everyone to spend their next ten years reading Plato according to your interpretation, as veryfew will do that. What you should instead do is present Plato's ideas to the world as an organized philosophical work,complete with arguments, making occasional reference to Plato, and then see if these ideas stand up to critical examination by other philosophers. When philosophers who are Plato-enthusiasts don't follow the correct route, I assume it is because they sense, correctly, that their beliefs could not stand up to critical scrutiny, but don't want to admit it to themselves.

That is why I turned to the question of what the author thinks is true, and could it stand up to critical examination. As I said, I think he is hiding behind Plato, and it seems to me you are doing the same, turning the question away from what is the truth to your interpretation of Plato.

And with that in mind, let me ask you, what is your metaphysics and what is your political philosophy? Also, for one particular topic, namely biology, do you agree that Aristotle invented scientific biology, and that this was a great advance? Or do you claim that Plato actually invented it, or do you agree that Aristotle did but that it was invalid and unimportant, or what? Ditto formal logic.