Methane hydrate is a geological hazard. No one has yet developed technology to mine it safely.
It wouldn't take much warming to belch a large volume of methane gas to the surface. You don't want to be nearby when that happens.
Green nazis will try to stop it out of fear of CO2. As though we can't simultaneously look for the thermostat controls. Green nazis have already killed more than 500 million people with their luddite junk science (see DDT), we shouldn't listen to them now on this, either.