Urban dictionary:  A person who never brings any joy.

We all know one, someone who poisons everything they touch.

That is all.

There is no better word at the moment.  Douchebaggery it is, and douchebaggery is afoot.  It feels good to say it.  It’s enough syllables to be complicated and hard to say after two or three times, but simple enough that everybody understands it.

The Urban Dictionary provideth: douchebaggery

1)The philosophy held by douchebags, holding that no one other than themselves (or perhaps their close associates) matters in the least bit, and thus that other human beings can and should be treated like complete excrement for little or no reason (and often for selfish reasons). Closely related to fascism, which has been practiced by control freaks such as Adolf Hitler.
2)The act of putting this philosophy into practice.

The other definitions there are similarly beautiful and true, I suggest you go and read them all.