Why do republicans anticipate a riot?

I work with all republicans and yesterday they kept talking about how the libs are going to riot since they lost. But in my lifetime (45 years), the only time there’s been any riot activity due to elections was Jan 6th. Where are they getting this? Libs aren’t the ones constantly saying the elections are rigged. Is it that they really have zero acknowledgment of Jan 6th? I just don’t get it. I know you can’t speak for them directly, but help me understand their POV