I like this for it's simplicity and logic. It's does make sense the criticizing, condemning and complaining have are more negative than positive impact. Despite this, it often feels so good to fall into the trap of these behaviors. Just like it is easy to get out of control in eating food that is bad for us.
That is an interesting side thought. Why does it seem that the "bad" things are easier to do than the "good" things? How often to you hear about someone who is out of control eating fresh fruits and vegetables? Do you often hear someone on the news saying "I just can't help myself, I know that there are all sorts of sweets and fattening foods, though I just can help myself from eating a well balanced, nutrition meal?" Isn't it more likely the opposite?
Is it a matter of focus? The news tends to publish what people want to hear and it seems most people want to hear negative things. "If it bleeds, it leads". I'm not so sure it is a matter of the media filtering what we hear. Look around you. Do people talk about how they can't help themselves from doing the right thing? Isn't it more thought of as a struggle to do the right thing? How many students talk about how they can't keep themselves from doing their homework and getting good grades?
How much of this is also a factor of what we define as "good" and "bad"? Last night I was in bed soon after 9pm. This wasn't difficult for me, it was a conscious choice and I was happy to do it. I went to bed at that time because I wanted to get up at 5am this morning. I know that if I go to bed at 11pm it is very difficult to get up early, therefore it was not difficult to go to be early.
So, maybe this also is affected by goals and our clarity towards our goals. If our goal it to have a long term healthy relationship with people, we should realize that criticizing, condemning and complaining will damage this long term relationship. If instead, we are only interested in immediate gratification and satisfaction, then these strategies may seem to have value. The same can be said for healthy versus unhealthy food. If we are focused on our long term health and well being then eating healthy is an easy choice. If instead, we are focused on the immediate pleasure, than the unhealthy choices may be the most attractive.
This is part of it, and there are still external factors.