If you're spanking your kids all it means is that you have failed in your role as a parent.
Bullshit. Kids vary widely in the sorts of things that they respond to. One of mine (we'll call him Bob) has always responded well to verbal remonstration and body language (the "look"). The other (Jim) does not. This has been the case for their entire lives. They're getting older now and removal of privileges usually suffices, but when they were little Jim could be punished by removal of toys, removal of privileges, removal of a desired activity and timeouts, but sometimes would just continue right on with the bad behavior. For him, attempting to exercise control over us by trying to make us angry was more important than avoiding punishment. When he really got up a head of steam, he became so single-minded that nothing would stop the behavior except a smack on the butt.
Now, you may be tempted to tell me that I didn't think of all of the alternatives, or that I didn't implement the ones that I tried correctly. The problem is that you don't know what you're talking about because you don't know my kid. I've talked to other parents who have kids like Jim, including some who know Jim, and they also hear this kind of nonsense all of the time. People assume that because they've been successful in using other techniques with their own children, that the success is due to the techniques. What they fail to comprehend is that the child's personality is a huge factor in which techniques actually work. This was a lesson that I had to learn the hard way. When Jim was little, I never thought that I'd spank him. We tried everything we could think of, including reading books, articles, blog posts, etc., getting advice from other parents, and experimenting with anything that we could think of. The bottom line was that none of it worked when he really got going.
As a contrast, Bob's bad behavior can usually be interrupted with a sharp word. In serious cases, raising our voices does the trick. Timeouts never fail to work with him, and he rarely takes it far enough to get one. Same parents, same gene pool, very, very different results.
My kid is probably an outlier in this regard, but he's not the only one that I know. If you've been able to find ways to discipline your kids without resorting to spanking, good for you. Don't be arrogant enough, however, to assume that your experience is representative of everyone else's.