"Socrates turns to a consideration of the physical training for the Guardians, which course in gymnastic should begin quite early in life and continue through life."
Broke: letting warriors set their own training schedule. Woke: letting Plato sit in his armchair and tell you how to exercise. Irresponsibility and classic scholar arrogance.
That said it's hardly impossible for a scholar to know more about the training regimen than a warrior does, but it requires a lot of Aristotleanism. Have to go look at the training yourself, observing closely, and to try a few small-scale tests. Further, this will get out of date. Even if you achieve warrior+ levels of understanding, if you look away for a moment, they'll learn things you don't know.
"The Guardians are to abstain from any form of intemperance: gluttony, drunkenness, or any form of sexual license."
Grassmonkeyism. Confusing obeisance to Satan's social dominance for piety toward the heavens.
Insofar as this sort of thing is accurate, it's a coincidence. I'm not saying drunkenness is good, but through history we can see repeatedly that Plato-types get wildly activated about vices with performance relevance at the sub-1% level. They're not trying to make you healthy, they just want an excuse to order you around. Rule in Hell etc; do Satan proud.
A bit of projection too. For warriors, drink is probably a straight-up good at times? It's scholars that need to avoid the sauce entirely. If you can't tell which brain cells were killed by a night on the town, you're not exploiting your brain fully yet. Train harder.
"Socrates proposes that the citizens be told "just one royal lie," a "needful falsehood."
Yeah bros, let's just worship Satan a little. Just a little though!
Veritas is a jealous bitch. If you cheat on her a bit she'll be a complete cunt to you.
To be fair, I'm biased. My faith in Veritas is unlimited. Fiat vox veritatis, ruat caelum. Vigeat veritas, et pereat hominis.
If you speak the truth and it doesn't work out for you, the problem was you failing truth, not truth failing you.
"Glaucon is extremely doubtful about the efficacy of this "royal lie" and so is Socrates"
...because it's an obvious mistake.