Strange still isn't buying this bullshit that Shima's trying to sell. Sure, he can yammer on about the magical properties of bonds, repeated actions, and emotional connections until the cows come home. But all of this is still so implausible. There had to be a better defined answer than just 'make friends'.

So, Strange is going to give Shima some bullshit right back.

"I meant that barely anybody else is responsible enough to be trusted with this. You've been here long enough, you've seen what passes for 'plans' around here." Half the time they just barely work, all of the time they're kind of dumb.

"Aside from that, we're a carnival full of teenagers. It's a bit degrading to have one's magical essence rest in the hands of someone who isn't even out of puberty!" That's said as he looks directly at Shima. He's not actively calling out the fact that hey Shima, you're technically still a kid, but Strange is certainly thinking it.