Is this unfair?

I am temp agency and I don’t think it’s fair that they’re making me train their new staff because I am the friendliest (most competent) person working here

When the supervisor told me I told him I don’t feel comfortable training their staff when I basically just do universal things that apply to every facility. and i not know the proper policies and procedures so I don’t want to be held accountable for training the staff incorrectly

The supervisor said it’s fine don’t worry about it

I’m still mad 😠 and think this shit is unfair.