Not true. Whoever wrote the code owns it, as per US copyright law (as I understand it). Now, if you release code under a copyleft license, it’s still yours — you’re the copyright holder — but you’re granting a license to other people to do whatever you allow them to in that license.
If Azer chose an open source license that allows other people to publish it, which it sounds like he did, then they have the right to do so. If Azer didn’t want this to be legally possible, he should have chosen a different license. But because he owns the code he wrote (as the copyright holder), he can choose to make future versions of kik under a different license if he wants, which no one else is permitted to do.