That lynching is a hate crime is a no-brainer. Otherwise it would be called hanging, murder, or both.
I wanted to address Ronald’s comment that we can prosecute murder and other crimes that involve killing another person but that we cannot (or should not) make laws about or prosecute emotions.
I am a Jew, and I belong to the generation that was born immediately following WWII and the Holocaust. I have experienced an underlying fear my whole life. My kids have this underlying fear, and I did everything I could to prevent it. I believe that African Americans experience a similar underlying fear, although I don’t want to speak for an entire group of people (or even another individual).
Hate that leads to actions like lynching and gassing people is a crime. This is separate from simple murder. You can premeditate murder or murder someone by accident, in the heat of passion, or by not thinking about others, as when you drive under the influence of alcohol or other drugs.
To lynch someone, you need to find a suitable tree, get rope, make a noose, get a group of people together, kidnap the victim, put the rope and noose over a suitable tree limb ... honestly, I feel ill just writing this. I’m not going to list the resources you need to gather or the plans you need to make and implement in order to murder 6,000,000 Jews and several million people who are gay, mentally disabled, Roma—it’s a long list.
This kind of hate is magnitudes different from the hate you see on Twitter or certain other places on the Internet.
The hate in hate crimes goes far beyond a simple emotion. That is why we need to categorize certain acts as hate crimes, enact laws to address them, and prosecute them as such.