What are you, in high school? In the real world, every source must be considered critically, and Wikipedia is inherently no more nor less valuable than any other source. Any epistemology which automatically and uncritically accords greater merit to "authoritative" sources, or lesser merit to "un-authoritative" sources is lazy, and itself without merit, value, or use.
What you've committed here is essentially a variant of the
ad hominem fallacy. Attack the content, not the source.
(Incidentally, if you bothered to check the attribution, that definition is from the WHO, and is as of much inherent merit – little, if any – as any dictionary.)
A dictionary serves no purpose other than to establish common ground; it cannot authoritatively prove or dictate the meaning of any word.
To further prove my case:
http://dictionary.reference.com/browse/violence
While one out of five does suggest value, the top two definitions are value-neutral. This strongly suggests that, absent any context, the word carries no value connotations. Further definitions are irrelevant, as the point is sufficiently made.
Any sort of physical force meets the definitional criteria for "violence".
Few states have sentence enhancements for "aggravated" rape. And even if they all did, it would remain irrelevant. Consider: "assault" is, by definition, violent. And yet there is also "aggravated assault". How do you explain this?
Anyway, since you love definitions:
http://www.bjs.gov/index.cfm?ty=tp&tid=31
Get real, buddy.