They could have this whole conversation without Rhys ever saying anything. He was that easy for Julian to read. In essence, if he had been allowed to they didn't have to have this conversation out loud at all. But Julian understood not being allowed in Rhys' head and it wasn't because of the secrets he'd find there. It was because of the danger Julian could be when allowed to wander in the minds of others who couldn't fight back.
When allowed to pick at minds as fragile as his own. Those were always the most alluring. All that anxiety. All that self-doubt. All things Julian understood all too well and tended to focus in on until he made it worse.
Yes, Rhys was far better off with Julian on the outside of his mind.
"You will be because you'll have to be. The court and your lover's position will shape you into what you need to be. Your lover's position offers you protection. It's protection that you will need to survive, especially now in the beginning when you're so new to the game." And in that Rhys would other learn to play it or he'd not survive. It always came down to that didn't it? Play or be brought down to your knees. "But you'll learn, grow, not only for yourself but to be the type of partner that isn't just protected but can support in return as well."