When you skip a commercial on your DVR that ad has already been paid for. That content provider has been paid.

When you block an ad on the web it's not being counted as an impression and the content provider is not being paid (if CPM).

They're very different in terms of money-flow. It doesn't mean devaluing an advertiser is better, but they're two different outcomes, even if it just means "no ads" to user/viewer.