Ah, but you see, "John" and "Doe" are two names - first and last - and when you say "My name is", you're really listing out your names, with spaces inbetween!

But then there's hyphenated names, and I have no idea how those are treated.

The Romans also had spaces in between words

Blank spaces arent characters by definition as they're the space that allows the letters to exist

No, they didn't even use the space to separate words. Take a look at any Roman inscription in Italy, there are no spaces between the words (just like there are no silent pauses between spoken words).