Assessing ridiculously low probabilities with no prior observations is a (ahem) “fine art”, not to be undertaken by the overconfident nor foolhardy, and obviously not “bad guys”.
In the case of high energy physics though, we are in the lucky position of having an enormous amount of confidence and consensus on the accuracy, precision and self-consistency of our current physical knowledge up to very high energy levels.
My personal take was, given we are quite confident there are quite extreme energy states available in large quantities only 8 light minutes away, and a super massive black hole 25K light years from here, along with all manner of lethal stellar events happening in the neighbourhood, I found it a hypothesis worthy of demanding extraordinary proof that on earth we would have an observable risk of managing to create a more cataclysmic event than our local environment has been able to manage.
Essentially, I was arguing the Universe has and has had quadrillions more opportunities to do this to us already.
That’s essentially an epistemological argument I feel.
A practical argument is that we are zapped by cosmic rays of apparently yet more extreme energies.
The review document is here and works though the numbers on my back of cigarette paper reasoning — and I learned a new word — “undecillion”, for the amount of time the Universe has tried to murder us all in our beds.