To be fair, I wouldn't want to keep most of the stuff that gets sent to them. But, I hate clutter, and would know better than to advertise the fact that I had a P.O. box. Their house looks like a flea market with all of the bad artwork, and knickknacks in every room. They need to designate one room for it, and keep the rest of the house nice.
Also, what goes through a person's mind when they go beyond just leaving a comment on a video, and think that it's a good idea to waste their time, money, and energy, sending online "personalities" (A.K.A. strangers) weird shit and long letters?