> Curious why I can't offload this task to a DNS server?
DNS doesn't provide nearly enough precision for ad blocking. Many servers serve both ads and content. Random example: some sites host actual non-ad video content on doubleclick.
Last time I looked through EasyList, it had some comments explicitly mentioning that they can't just block all of doubleclick because some sites (such as news sites) host their content videos there.
DNS doesn't provide nearly enough precision for ad blocking. Many servers serve both ads and content. Random example: some sites host actual non-ad video content on doubleclick.