He only says, 'Good fences make good neighbors'. Spring is the mischief in me, and I wonder If I could put a notion in his head:
In response to the apples-aren’t-carnivorous argument, the neighbor simply says, "Good fences make good neighbors."
Believe it or not, this is a famous proverb (a common saying that expresses a truth) around for centuries. You can interpret it how you will, but we take it to mean that this neighbor likes his privacy and his own space.
If he posted an ad on Craigslist, looking for a new roommate, it would probably read something like, "Quiet person seeks even quieter roommate for a two-bedroom apartment. Roommate must stay clean and keep to him/herself."
Our speaker becomes a bit mischievous, however (spring will do that to you). He desperately wants to stir the pot and challenge the "good fences make good neighbors" proverb. He wishes that he can somehow inspire his neighbor to rethink the whole wall thing.