H.R.35 Research

I just learned that lynching has finally been made a federal crime. It was a unanimous decision by the House. Apparently the maximum sentencing for those who conspire in the process of lynching is 10 years, which seems much too lenient for such a heinous crime. Or, as I'm rereading it, it seems to be using 10 as an example and saying that co-conspirators may not serve a sentence longer than someone who completed the act of lynching. The main question that this prompted from me is this. Why the heck did it take so long to make lynching a federal crime? Also, who are the people who are in favor of lynching (or don't like the bill in general) and why?