Because Teleportation involves breaking down the atoms of an object and piecing them together in a different place. Talons don't look capable of holding atoms in place (they're open enough that you can dodge roll out of them with minimal damage to your body) so logically, teleporting away from Talons is completely possible.
I understand your point, but streaking out of Talons is actually worse than rolling them. You don't get root immunity and you don't get to choose which direction you move - you move in whatever direction you were oriented in when you got rooted. Not to mention you remain rooted for the duration if you don't roll (if I'm not mistaken). Honestly it feels fair to me.