That article reads like it has a very large political axe to grind. While empathy may have decreased due to some large-scale social changes, blaming the "self-esteem movement" is confusing correlation with causation. I'd be curious to know, for instance, if people in urban communities score lower empathy than people in rural communities.

It seems reasonable that a lack of empathy and grandiosity would be associated with violent behavior, but I don't think it's meaningful to call this "self-esteem" or blame a movement that tries to make people feel better about themselves. There's a problem with your measure of self-esteem if it correlates with not being able to admit when you're wrong: that shouldn't be called self-esteem! A secure person is more likely to admit when they're wrong.

The survey in the first article measures empathy; I don't see the self-esteem surveys anywhere, but that last link says

it may be more correct to say that a form of high self-esteem -- more precisely, a highly favorable and possibly inflated view of self that is confronted with an external threat -- leads to violence.

That final article also refers to 'egotistical' and 'arrogant' as terms of "high self-esteem". While it makes sense that egotistical and arrogant people may be more likely to be violent, it's highly misleading to call that having high self-esteem. The article seems to be talking more about lacking the ability to react well to criticism, which sounds more like low self-esteem, not high. (That final article does note that many of the scales that measure self-esteem may be biased either negatively or positively.)

(Edited to make clear which article I mean in the last paragraph.)