Is vilenkin justified to reject the kalam?

Vilenkin attempts to evade the first premise of the kal;m cosmological argument: 'Everything that begins to exist has a cause'.

He justifies himself saying that such an event does not violate one of the natural laws, namely the + and - energy do equate one another if the Universe appears our of nothing uncaused. But the metaphysical laws are harshly violated with this assumptions, it is like claiming that if the concept of 'married bachelor' does not violate one of the natural laws, it is still metaphysically possible.

The man who thinks that 2+2=5 is as much mistaken as the man who thinks that raping little children is not wrong.

Which is more, Chris Isham, UK's leading cosmologist, points out that an 'ontic seeding' is anyway needed, or simply speaking an initial cause for the energies to balance and launch the entire Universe; so the Universe cannot go uncaused even only according to Vilenkin's justification, leaving the metaphysical laws aside.