Why did I fail NY inspection

I need an inspection on my car. My engine light was on. A friend was able to
reset it so the light would no longer be an issue.  He told me to drive around for
about 40 miles before going to get it inspected. I drove about 50. Light was still
off but failed. It says Readiness failed; Monitor catalyst not ready; Monitor evap
not ready; Monitor O2 not ready. Now I don't know much about cars but from
what I'm reading on the internet I see that getting the "not ready" results means
that after my friend reset it the monitors still weren't on and that's why I didn't
pass. Not necessarily because something needs to be fixed. What I'm confused
about is if I'm correct then why did the mechanic tell me that if it wasn't for the
O2 coming up I would have passed and that I need to put in a bottle of
"guaranteed to pass" in my fuel tank as if that is going to fix what made me fail.
Wasnt it the monitors not being on yet that made me fail?