No one agrees with hiring people to fill a quota over those with merit but that's not the whole picture. I'm sure that has happened at times but I have some inside experience with this because we have clients that asked us to diversify our workforce(Apple for one) and my cousin is a Sociology professor in NC.
It's more about making sure that a wider pool of qualified people are aware of your openings by placing ads in media they consume or through outreach to orgs like the Latin American Chamber of Commerce, for example.
There is no requirement that you hire people who are less qualified, it's more about adding them to your pool of applicants. For my company, it was more about adding people, not subtracting or giving a job to somebody less qualified than another. Others may have a different experience but all in all, I do think having a diverse workforce that reflects the poulation as a whole is a net positive.