in NY, first degree murder only applies to the killing of a police officer. if the 14th amendment was as you claim, I am sure some NY lawyer defending a cop killer over these past years would have gotten some court to agree - so far, they haven't, so my guess is that your interpretation of the 14th is incorrect.
My interpretation is correct. The fact is, there are a lot of unconstitutional laws on the books. Hate crime legislation comes to mind.