Podcast ads suffer from the same issue as most other ads, which is that they're primarily lies intended to manipulate your emotions and influence you to act in ways that are against your self interest.
You know, sometimes that's true, but sometimes they really do just communicate what a product is and why you might want it. There are a couple podcasts I listen to where the ads are almost uniformly worthwhile — for someone, if not for me. Podcasts with obstreperous or manipulative ads tend not to be worth listening to anyway; good podcasters value their audiences too much to insult them.
That is indeed an issue with advertising, but it's not the same issue as with most other ads; at least not the one most people object to, which is the privacy and security violations of comprehensive tracking of personal information delivered via exploitable, executable code.
I believe most people object ads because they find them annoying, people who worry about privacy and security as the main reason are a minority (maybe more expressive in HN, but not in the general population of ad block users).