This brings up an interesting question. Ownership. To steal, you need to have ownership. Who “owned” the pamphlets? the JWs seemed to give them away. The other recipients had not accepted or rejected them.
What was stolen and from whom?
This is extremely elementary, the JW transferred ownership from themselves to the specific people whose mailbox they placed the book on by virtue of having placed the book there with that intention. The book became the property of whoever owned the mailbox, whether they knew it or not.
They are giving them away to be sure, but they are doing it in a specific, controlled manner, one per mailbox, on individual mailboxes. The OP got his. It was his to with as he pleased, read it, throw it away, burn it, he can even choose to use it in his outhouse if he wants that’s his business.
If my mom sends me a birthday present by UPS and the UPS guy keeps it he’s stealing from me. Even if I don’t know it exists. If the UPS guy leaves it on my porch, and the OP comes by and decides that the present will endanger my soul and takes it and burns it (to “save” me) he is stealing from me because it was my property. It became my property the moment Mom consigned it to UPS.
If a cereal company decides to give away free samples in my neighborhood and leaves a small box of cereal on each mailbox in my neighborhood. The OP tries it and likes it, he’s not entitled to go around and collect the other samples because they “don’t belong to anybody”.
If he sees that the cereal is loaded with preservatives or uses refined flour he’s not entitled to collect and throw away all the samples in the neighborhood “for our own good”.
This applies even if the OP doesn’t know who he is stealing from. A UPS box sitting on my front porch (or a book sitting atop my mailbox) clearly doesn’t belong to HIM. Its not necessary from him to know who it does belong to. It is enough for him to know the HE doesn’t have just title to it and should therefore leave it alone.
Similarly it doesn’t matter if the item has any monetary value. If the present my mom sent me is nothing more than a brief note of affection penciled on the back of a piece of scrap paper it still belongs to me and for the OP to appropriate it for himself is theft.