Threatening people is wrong. What is hard to understand about that? It seems some people don't get it. But really it is because sin has gotten into their hearts. The sin in question is hate.
When people make death threats hate is at the core of the action. We are supposed to love our neighbor, not hate them. This hatred causes people to be unjust. Threats concerning a person's business are wrong too.
Two cases in point are the Oregon bakers that were fined for not baking a wedding cake for two lesbians and the Florida baker that refused to bake a cake that stated, "We do not support gay marriage." Haller, the Florida bakery owner says that people started calling the bakery making vile remarks and threats to her business.
Both bakery owners received threats. In either case, the people making the threats are wrong.