People like Laci Green are annoying.
As TA said, they contribute nothing. There is nothing necessarily wrong with being an SJW, although I think the term SJW is stupid and ridiculous. The term "advocate" is more suitable.
The problem is that these SJW's scream, yell, and argue poorly. They do not understand how to advocate in an effective, appropriate manner.
I consider myself an advocate for certain causes (not racial or cultural causes), but I would never call myself something as degrading and childish as a "Social Justice Warrior."