@yorabits,
There is a lot into play here - is this a hard to fill job? Do you have a lot of turnover? How much skill and how specific a skill do you need? How important is it to fill these positions quickly? How much training is required once hired?
Yes having diversity is important, but did your manager have issues previously going the other route? Perhaps reaching out via refer a friend is easier and maybe she has had more luck this way with keeping employees?
It really is hard to judge on whether this is the best tactic or if she is just taking an easy way out.
If you are close to your manager, I'd just tell her straight out - I am concerned that we lack diversity - is there a different way we can recruit to get a more diverse staff? Also are you of this same age/college? If not, then you should have reached out to a friend even so - do you know anyone that you could have referred that has a different background to help diversify your team?