I am embarassed that I have to explain jokes.
(1-3) in my 5970 are a direct and honest response to your question why are we to preach to animals.
(4) is a joke to illustrate that 2 Timothy 3:15 applies to Protestant Sola Scriptura theory just as good as 2 Timothy 3:14 applies to animals (they do learn if you teach them, continue in what they learned, and know their master).
Don't be embarrassed.
If it wasn't funny, it's not a joke. It's an attempted joke.