Did I slander him? I criticized the policies he votes for and his thought process.

I did not slander him as a person, I criticized his way of thinking.

I did insult his hypothetical city, but we're discussing the cause as to why cities are shitholes, it's not slander when it's true.

He wants proof that being lax on crime perpetuates crime, yet ignores decades of basic criminology due to a wikipedia criticism section with no substance.

Words have specific definitions, not what you want to stretch them to to make your snarky point.