There's a thousand things that can destroy your house if you use them wrong. Leave the stove on, turn the gas on without lighting it, store loaded firearms in the oven, extension cord trees, breaker bypasses, tinker with any utility, any number of cleaning products, cars in general, water leaks, just leaving the water running, space heaters, portable generators, shorting the terminals on a battery, the list goes on.

And preventing the use of the toaster sideways won't fix the problem anyway. People will still cram extra stuff in there, and overcooked toast can catch on fire without much provocation. Even just forgetting to clean the crumb tray can cause a fire. Trying to foolproof a toaster just gets you an incredibly expensive device that rarely works.