Are you disputing that 5 people died in the Capitol insurrection on January 6, or that it was caused by the far right? This is a clear example of "dangerous", is it not?
These were the people that the GitHub employee was referring to as "Nazis", although not 100% literally: I'm sure that not all of them were actual Nazis, many were likely only Nazi sympathisers or other violent authoritarian fellow-travellers.
https://www.theguardian.com/us-news/2021/jan/08/capitol-atta...
At least 25 people were killed during the “peaceful” BLM protests this year. The article implies that 11 is a more accurate number.
https://www.theguardian.com/world/2020/oct/31/americans-kill...
Both of these numbers are minuscule, on the order of people killed by vending machines and bath tubs. So they are dangerous in the sense that bathtubs are dangerous.
https://www.theguardian.com/theguardian/2010/dec/07/things-l...
Comparing the numbers equates the degree of the danger, not the kind. They are dangerous in a very different sense, that of intent: Bathtubs do not chant slogans calling for anyone's death, while carrying out an armed attack.