Because.
Also, flamethrower aren't considered weapons by the government, so the only states that limits you from buying one is California and Ohio and Maryland banned them.
California allows roofers to have flamethrowers. They use them for curing something in the roofing tiles(? I don't know the proper term for those things. They're basically cardboard covered in tar and gravel, possibly a thin layer of asphalt?).
It was a bit unnerving the first few times I heard the roofers doing their thing.
Where’s the robot to clean up the flaming, decapitated gopher carcasses off my lawn?
Not needed, because they get flamed while they're in their burrows underground. So all you have to do is plug up the holes after the bot comes out and you're done.