MakeGamesWithUs is about making, creating, learning. We teach them for free where many others would charge, then give them the option to publish with us if they would like to. It's entirely their choice to publish with us, they are free to publish their games on their own. We also only take 30% of revenues, not half.
Since many of them are minors their parents have to sign off on them attending the internship and publishing with us. The fact that 100+ parents have agreed to let their children intern with us and 30+ parents have agreed to let their children publish their games with us is a testament to how good of a deal we offer them.
I am aware of developers who have literally gotten their careers started thanks to us, as in gotten jobs as mobile developers by showing off the games they built with us. Nothing exploitative about it.