Factual error: In the scene where the angry mob is attacking the Simpsons in the tree house, Grandpa Simpson is shown aiming a double-barrel shotgun, which he then pumps to ready it for firing. There's no such thing as a double-barrel pump-action shotgun. (00:36:20)
Factual error: Marge, Bart, Lisa, and Maggie Simpson take the train from Alaska to Seattle, Wash. (The train shown in Alaska, is the exact same one that arrives in Seattle). This is not possible as there is no train, (passenger or freight), that links Alaska to the southern 48 states, including Seattle, Wash. Homer Simpson does not take the train to the southern 48 states.
Answer: Homer has been known not to make the smartest decisions, and the decisions he does make, he makes without fully thinking them through. Clearly he wanted to get some donuts as quickly as possible without thinking of any other ways, so he decided to ditch the silo in the lake as it would be the fastest way of getting it off his back, even if it's not the smartest. Also, putting that aside, he likely wanted his own pick of the donuts rather than have Lenny guess what he wanted.
Casual Person