I am trying to get some clarity on this. I am not looking at personal or risk mgmt perspectives. 

Why do we need to protect passwords (or 1st factor) in the context of 2fa (or multi factor authentication) because hacker won't have second factor.

A similar but not exact is to trivialize 1st password to say abc123 and argue hacker won't have 2nd factor ? 

What are some technicalities not to let guard down on passwords in the context of 2/mfa?