Going by the extracts, the agreement out to him might not do what he says it does.
There might be diverting in the definitions that changes that, but I doubt it. More likely, this guy is just being a jerk who is too cheap to pay a lawyer to review the agreement and advise him, even though it seems he has the money to do so.
From TFA, it seems that IFTTT has just gotten it's hands on done venture capital. One of the first things incoming venture capital will do is require regularisation of important ad hoc legal relationships (including making sure that all necessary copyright licences are in place), so this change would not be unexpected.