Milhouse, if someone asks you to meet them at 12 PM, you might show up to their house at midnight? In all the years I’ve never heard noon referred to as 12 AM.
I won’t argue about what’s technically/linguistically the correct terminology or usage, but as a practical/real-world usage 12 PM is unambiguously used to refer to the afternoon and 12 AM is used to refer to midnight. I’ve yet once to see it used in the reverse of that.