Those who think that A16Z—and many other VCs per se—started their own media arms or at least blogs to "help industry" probably lived under a rock. There are just 3 reasons for a VC to invest in its media arm:

1. Help to create a deal-flow by writing about a current thing or their specialization in tech;

2. Promote its portfolio and pump it in every possible way for it to increase in value;

3. Promote its agendas and narratives like regulation/untiregulation.

So, yes. A16Z's media channels are a marketing tool.