You may not be stealing directly from the people whose works you are entertaining yourself with, but you are stealing from the people whose works you would have otherwise bought if you didn't have this free entertainment that you consider unworthy of your purchase yet still view anyway.

If you enjoy content and declare "It isn't worth the price, and I wouldn't have bought it anyway, so what's the harm, right?" you are still satisfying your urge to be entertained. If, without this access to free, overpriced entertainment, you would have otherwise sought out and bought other entertainment that you deemed worthy of your money, you are stealing from the people offering worthy entertainment.

If someone owned a practically infinite supply of water from a spring and bottled water for $50 per 12 oz bottle, and you said, "Hey it's fine if I sneak on their land and drink from their spring, because I wouldn't pay for their water anyway, so who am I hurting, right?" regardless that there is tap water that you would have otherwise bought at $0.03 per gallon, but now have no need for.

You may not be hurting the spring owners, but you are hurting the utilities selling the tap water.

IMO, this is why entertainment mostly sucks nowadays. It's very hard to make any money in it, because people are all watching/listening to crap movies/music, turning their nose at it and refusing to pay, and then going in for a second helping. /rant