I can't recall aiming to summon dragons specifically, but opening up gateways and generally working with the otherworlds is something I have experience with.
The spell is garbage. I imagine it wasn't meant to be taken seriously, but it's still garbage.
I'll grant different practitioners have varying philosophies on these things, but let's think about this for a moment. Do you want a slave or do you want an ally? If you want a slave, do you really think you can bind it to your will? To my mind, summoning a powerful otherworldly entity and making demands of it - regardless of protective measures - is just a stupid idea. It's no way to cultivate relationships... whether in the otherworld or the apparent world; it would reflect poorly upon my character as well.
But... again... I imagine this wasn't meant to be taken seriously. I hope.