You might think it's unreasonable to build such a house-burning robot, but you have to realize that I actually designed it as a lawn-mowing robot. The robot will simply not value your life or property because its utility function is descended from my own, so may burn your house down in the regular course of its duties (if it decides to use a powerful laser to trim the grass to the exact nanometer). Sorry neighbor.
What do you expect me to do? NOT build this robot? How dare you stand in the way of progress!