Do you know how scared I am that someone is going to have to shoot up the NRA convention for anything to change
That's a bit extreme. Did you do something that might have given people this idea?
I've recently posted something similar on facebook.
Violence shouldn't be a solution to getting things done. It's quite scary what people will do because of what they see online. If someone does shoot up the NRA then what you had posted on Facebook can be used by the FBI as instigating the shooting and you might face legal ramifications.
I didn't expect them people to take me so seriously.
Yeah, people tend to take things seriously when it comes to sensitive political topics. I don't think you should feel responsible for anything that happens, which I doubt it will, but next time be cautious with what you say online.