We mine with Augar one way or another - just other resources.
Methane-clathrate is a free fuel that simply lies around - why not go and pick it up?
Using sebatier has it's limits...the main limit is: It uses WATER or HYDROGEN which are RARE on Mars. On the other hand - ther's nearly unlimited suplies of clathrates in underground vents.
Sebatier uses a LOT of energy (Double Water electrolysis, cryogenic coolers, charging/heating electrodes etc..).
Sebatier can BREAKE, and untill you fix it...from where will you get methane fuel? You can mine it!
I can't thing to compare this situation to mining Oil on Earth....why not simply CREATE synthetis Oil? We know how to do it on Earth...we did it in WW2. Why not now? Becouse it's not economical. It's easier to dig the fuel than to create it. And yes...peeple die for Oil.