I don't disagree that as a consumer you should have the right to choose what gets sent to you - but generally, if you're using a site, you're also consenting to its terms of service (which generally include accepting its ads.) As such, the product IS actually defined for you, and not up for you to define as you see fit. Using it outside of those terms is theft of service.
If you don't want accept those ads, fine, but from an ethical and legal standpoint you shouldn't be consuming its content or using its service, either. This whole "the users are the product" thing sounds great but it's an oversimplification; ultimately, it's the user's consumption of advertising that's the product for an ad-supported site; the user itself (ex ads) is often worthless or less than worthless.
You're making a deal with the provider of the site that you'll consume their product in exchange for also viewing the ads; if you don't like that bargain, don't accept it and don't consume the content.
The fact that you pay for your bandwidth, btw, has nothing to do with the fact that the site also pays for its bandwidth. Your ISP is not using part of what you pay to cover the bandwidth costs of the content provider.
To take this line of reasoning a step further, you're not really acting in good faith if you view the ads without ever buying the products or services they advertise. The advertiser pays the provider of the site in the expectation of a reasonable conversion rate. If you don't want to buy a certain reasonable percentage of products advertised to you, fine, but from an ethical and legal standpoint you shouldn't be forcing them to waste their advertising budget on you. Doing so diminishes the advertiser's incentive to support the site whose content you're consuming.
Here are some terms of service for you. When you enter into any business venture, you accept the risk of it not succeeding. Wishful thinking notwithstanding, the consumer is under no obligation to indemnify you against it.
Advertisers either pay for impressions (CPM) or clicks (CPC) or directly for conversions. They don't pay for conversion rates - if rates are too low, they might not buy CPC or CPM campaigns any more, but you can't generally get a refund for a CPM campaign because your conversion rate was too low (barring clickfraud.)
When you change channels, you're no longer consuming the content on that channel. It's closer to using a TiVo to skip the ads in a programming. I do it myself, but it's pretty obvious to me that if everyone did it, it wouldn't scale and they'd find some other way to create revenue like more product placements during the show (which is already happening) that's even more intrusive and obnoxious, because it's unlikely that providers or consumers are going to go a-la-carte.
(This is also why I liked paying for content on iTunes or Amazon - that seems like a more fair deal where I don't get both charged and ads (cable) and I don't have to mess around with using the TiVo to skip ads.)
If you're going to consume the editorial content of the site? The ethical and legal (if not practical) answer is yes. It's your obligation to understand and accept the terms of a service (not just a web site) before using it.
Is that impractical? Yes. But when I rent a car, I don't read the terms either, and they still apply. It's just a result of a world in which we undertake hundreds of "transactions" a day with business entities, all of which have to be governed by legal agreements.
If you don't want accept those ads, fine, but from an ethical and legal standpoint you shouldn't be consuming its content or using its service, either. This whole "the users are the product" thing sounds great but it's an oversimplification; ultimately, it's the user's consumption of advertising that's the product for an ad-supported site; the user itself (ex ads) is often worthless or less than worthless.
You're making a deal with the provider of the site that you'll consume their product in exchange for also viewing the ads; if you don't like that bargain, don't accept it and don't consume the content.
The fact that you pay for your bandwidth, btw, has nothing to do with the fact that the site also pays for its bandwidth. Your ISP is not using part of what you pay to cover the bandwidth costs of the content provider.