I'm going to take issue with your wording because, if you trace it down the pathways of the program provider/viewer social contract, the conclusion that would follow from that is that the viewer has the moral obligation to make the advertised product a success; i.e. he is morally obligated to buy.
I'm not saying that.
But let me split a hair here.
If you watch the ads and buy nothing, you have met your requirement. You do not have to buy anything to 'pay' for the entertainment.
But the hair I'm splitting is that of course, while everyone is free to buy or not buy, the system only works when the advertising is profitable, so some need to buy to function.
However, that's not a 'moral issue' like skipping the ads is. Worst case, everyone who watched the ads does not buy, and tv shuts down. Or not many buy, and budgets go down, and there are fewer choices and/or lower quality shows. But this is a theoretical issue; in practice, advertising gets results on average.
A further hair to split is that you are a good faith consumer who is open to buying advertised products, not someone refusing to do so, but no need to get into that.
Because of the vagaries of advertising in which an ad may only hit a particular demographic, because the number of advertisers does set up an internal market in which any one advertiser may fail without disrupting the whole system, and because there's really no inherent right for the ad revenue-driven programming system to even exist, I'd say you can't attach it to morality.
The morality here is in taking the product of others - the entertainment they produce to sell you for the price of watching ads - without paying the price for it.
People with DVR's are like a group who find a hole in the fence at a theatre, and sneak in and watch the show without paying, leaving others to pay the costs.
When more find the hole and sneak in, ticket prices go up on the others, udgets go down for booking acts; when everyone sneaks in, the theatre closes.
If you skip ads you're an ass and a leech on the system -- by all effects you are stealing content -- but I wouldn't say it's immoral. You're merely engaging in the technical destruction of that particular system.
I'd say choosing not to watch tv at all is what you are describing - and is the 'technical destruction of that system'. Taking the product and not paying is 'stealing' as you say.
This is an old debate among digital pirates - when the cost of distribution is virtually free for one more consumer, how does that hurt anyone, they didn't take a hunk of gold.
It's analogous to asking, if you watch the concert from a hill outside the theatre and it doesn't cost anyone anything, how is that 'stealing'?
It's a longer answer, but the short answer is, because the business model to pay for the creation and distribution of the entertainment relies on the people who want to consume it paying for it (by watching ads), there is an implied mutually beneficial contract you are agreeing to by consuming the product, to pay for your fair share.
I won't get into more obscure issues, such as, if you pirate a game you wouldn't have bought or sneak into a movie you wouldn't have paid for, but that prevents you from buying another game you would have bought or a movie ticket for a movie you would have, that harms those other products. Common sense: people owe something for these things they use.