How is this fair for DRK?

[TouchandFeel]

*drinking is better then wetting. cause he feels like a vampire: healing while punch stuff.

It's whetting, not wetting.

The word whet means "to sharpen" with the most common usage being in reference to sharpening a blade. That is where the name for a whetstone comes from.
The other usage, which is a little more archaic, is in reference to appetite, like in the phrase "to whet ones' appetite", meaning to "sharpen"/increase ones' appetite.

"Bloodwhetting" is just a playful usage of the word that implies an appetite for blood while also referencing the sharpening of a blade, like the one on their axe.
I also wouldn't be surprised if it was intentionally made to sound like bloodletting, which is the old practice of carefully draining a persons' blood thinking that it would cure them of different ailments and/or reinvigorate them by getting rid of the "bad blood" from the body.