I don't know what is worse. The fact that they don't understand intelligence testing or that they think that unless there is a center for it in the brain, then it doesn't exist.
Modern IQ tests consist of multiple sub tests - 15 for the WAIS IV. General intelligence "g" or a combines score is a weighted sum of the abilites in all these sub tests. A competent psychologist will look at the sub test scores for a richer interpretation, but that doesn't mean that the combined score is useless. General intelligence is based on the observation that people who are smart in one area tend to be smart in other areas (unfair though this may seem). Of course, this isn't always the case and sometimes people who are smart in one are are not smart in other areas. It is more accurate to think of modern IQ tests as a combined measure than as a single measure.
Think of it like CPUs. A combined benchmark like specmark or passmark can not fully characterise CPU performance, and sure, if I want a precise comparison, I need to define exactly what my load will be, yet you will be hard pressed to find a work load which a Pentium 3 performs better than an I7. So it IS useful to have aggregate measures of performance - so long as they are no over interpreted.
Some people don't like IQ tests because they see them as discriminating against socially disadvantaged groups, or racial groups. It is true that there is an issue of cultural bias in IQ tests, which people try an eliminate but can never do so completely. However, used properly, IQ tests can actually help people from disadvantaged backgrounds by identifying those with academic ability which may not be manifesting itself as academic performance for other reasons.