Most IQ tests - at least ones I've seen - are highly trainable, both in general (you learn to think certain way) and in particular (you learn to solve specific type of test). So while tests aren't race-dependent and there's no reason to think they might be, they definitely can be culture-dependent and income (or, more precisely, education level and type) dependent. So while the test is an objective measure, it in an objective measure of test performance, which may not be strongly correlated with the actual work performance. Remember those "move the mount Fuji" interview questions which were so in fashion some years ago?
I'm not saying banning them completely the right answer here, but putting too much faith into these tests can be dangerous too.
I've taken a bunch of IQ tests over the years with some wildly different scores. I score pretty well. I'm also very sceptical of their general utility.
The between the lowest and highest score I ever received on an IQ test is 45 points. That really doesn't sound like an objective measure of anything much (The lowest was when I was stressed, running on no sleep, the test was sprung on me with no warning and had US cultural aspects when I'm from the UK - things like talking about quarters and dimes. The highest was when I had practiced math & logic problems to win a bet that I couldn't add ten points to my IQ :-)
I find the idea of anybody using an IQ test as a factor in employment laughable. As far as I'm concerned any company using an IQ test is hanging a big red sign on the front of their organisation that says "we don't understand what kind of employees we want".
Such tests can play the same role as the famous FizzBuzz test - to quickly filter out obviously unfit candidates without spending much resources. But this is usually fit for very big companies that hire a lot of people, sometimes without proven experience, and have somehow to reduce costs of that.
I'm not saying banning them completely the right answer here, but putting too much faith into these tests can be dangerous too.