If this was only seen on Fox and the other networks didn't carry it, that is a bad sign.
This is the set-up.
Show this speech only on networks likely to attract Trump supporters, but NOT to the rest of the population.
What this does is attempt to rile up Trump supporters into doing something violent in reaction.
And If something violent does happen, the populace will most likely never know what prompted this.
Biden proclaims they're insane and must be rounded up, half the population never really knowing or caring that Biden prompted this. Except it may not go that way as intended and go exactly opposite.
I'm tired and don't know it that makes a lot of sense right now for what it's worth