No, that is actually the definition of hate speech in many countries. The big difference is that it is explicitly about dangerous speech directed towards groups based on bigotry, racism, sexism, homophobia, etc.
Another big thing is that the US law makes it incredibly difficult to prosecute for threats of violence and it needs to be an explicit, direct threat of violence. This allows you to effectively incite violence provided you never explicitly say something like "We need to go out into the streets and start executing the Muslims". You're absolutely totally allowed to build dangerous narratives that inevitably lead to violence.
Your founding fathers were also slave owners... Just because they did or believed in something does not automatically make it just, good, and sane government policy 230 years later, lol.
The first amendment was written in an era prior to quick, easy, and mass communication—even the damn telegraph was not invented yet. While words have obviously had tremendous power since the dawn of time, things are very different now that you have the ability to mass spread violent propaganda in a matter of seconds.
