Now, imagine a mutant in that population that causes people to pay attention to a cultural trait that is more highly correlated with genetic fitness. As these mutants have higher genetic fitness, they increase in proportion of the population, and cultural and genetic fitness are now more correlated. Cultural fitness now promotes genetic fitness. In the long-run, the two will be perfectly correlated (the exception being where cultural traits are neutral to genetic fitness).
Of course, it is well known that deleterious memes are widespread. The obesity epidemic is one example. The smoking epidemic is another example. Cultural and genetic fitnesses are not, in fact very well aligned. So, there is something wrong with this argument.
To see what it is, imagine we are talking about DNA-based symbionts - such as bacteria - rather than cultural symbionts. It is true that genetic mutations in the host that improve relations with 'good' bacteria, and hamper relations with 'bad' bacteria will often tend to spread. However, the bacteria themselves are rapidly reproducing and very numerous. In practice bacterial pathogens have a field day, causing all manner of infections to their human hosts, by simply out-evolving their defenses. Plus the immune system has to compete for resources with all the other organs in the body - including important ones such as eyes and gonads. It's just not going to be perfect.
In Jason's defense, he does go on to say:
The catch in that last sentence is the “long-run”. As cultural evolution can be so much faster than genetic evolution, systems can be far from genetic equilibrium until the genetic response evolves. Fertility in developed countries would be an example of this. There may also be some constraints that prevent perfect alignment, such as the presence of appropriate learning mechanisms.
For some reason, many evolutionists seem to ignore the deleterious aspects of culture - simply treating it as adaptive for its human hosts. Culture, after all, is what resulted in the human domination of the globe.
Yet, look at Japan. It is one of the most culturally-advanced nations on the planet - and the natives have sub-replacement fertility of around 1.3 kids per woman. The extent to which meme interests oppose gene interest in the modern world is enormous. The signs suggest that the conflict of interests between them will increase further in the future, as memes grow in power and numbers, and approach their crescendo. Memes have already overtaken genes on the internet. This is still just the beginning.
Jason closes his article with some highly dubious claims about how cultural evolution differs from the familiar kind:
El Mouden and friends note that there is a host of complications not present in the genetic case. Cultural relatedness can vary wildly across cultural traits, whereas the nature of genetic transmission means that relatedness is similar across most of the genome. Recognising the pattern of inheritance is also a challenge, as ancestor numbers can vary in number and be of vastly different biological ages. In that context, there is no such thing as a standard length of generation.
In fact, although cultural relatedness can vary wildly across shared cultural traits, this is much the same as how genetic relatedness can vary wildly across shared symbionts.
Similarly, DNA-based symbionts can have very different biological ages and average generation lengths.
Cultural and organic evolution only look different in these respects if you choose not to see how they are related.