No one could be more sympathetic to the application of evolutionary biology to human affairs than I am, and I have made use of many of its tools. But group selection and memetics have been unhelpful, and even evolutionary psychology in its totality can take us only so far. That is because human cultural change is driven by ideas. In the case of language, they are the lexical and grammatical analyses by which listeners make sense of the speech of others; in the case of violence, they are ideologies by which people justify their collective actions, such as religions, Marxism, nationalism, utilitarianism, enlightenment humanism, romantic militarism, and many others. If you reduce these ideas to simple tokens that are spread by contagion or multiply at different rates, and don't considering how their content affects the beliefs and desires of human protagonists, you will end up with a seriously incomplete understanding of cultural change.
It is true that if you reduce ideas to simple tokens that are spread by contagion or multiply at different rates, and don't consider how their content affects their human hosts, you will end up with a seriously incomplete understanding of cultural change. The problem is that nobody ever advocated developing a complete understanding of cultural change by doing that in the first place. This is just a ridiculous straw man concocted by Steven Pinker. He doesn't bother supporting it by any references - because he has none.
Imagine someone saying that if you reduce parasites to genes that multiply at different rates and don't consider how they affect their hosts, you will end up with a seriously incomplete understanding of disease. That would be pretty ridiculous. Nobody ever advocated attempting to understand disease in this way in the first place. This is not a criticism of genes or genetics, it's a misunderstanding of what these concepts mean and how they are applied.
Yes, there are people using "bean-counting" techniques on genes and memes - in population genetics and population memetics. But these folk are not fooled into thinking that frequencies are everything. Frequency analysis is just a tool.
Steven Pinker's closing criticism is a straw man attack. If that's what he thinks memetics is about, it reflects poorly on his understanding of the subject. This puts him in a poor position to offer criticisms - though he doesn't seem to realise this.