The fact people actually believe that there are enough gun-owners out there to overthrow the government seems quite optimistic to me. They have the presumption that every local, state and national police force will join with the people, not the government for which they are already a part of, and won't use their far superior firepower against them. They feel that, unlike all the people they see rioting and protesting against local government in other communities (which are often led by minorities or the poor), police forces will know that their attempts to seize/overthrow the government will be right and just, and SWAT teams will join their side as they march to the White House, rather than following their chain of command and years or decades of training to protect the country from threats both foreign and domestic.