What matters most of all is what was said, not the interpretation of the wording according to any listeners(s), or the response made by any listeners.
When talking about the crime of incitement to riot, the response of the listeners not only matters, it's pivotal. Without the riot, there is no crime. You can't incite to riot without a riot.
But that's criminal law. If you want to bring a civil action against Schumer for inciting a non-riot, feel free. But if you can't show damages (ie an actual riot), I highly doubt a judge would find in your favor.
To give an example, there are a couple of exceptions to the idea that it's illegal to yell "Fire!" in a crowded theater: when there is, actually, a fire; and when it doesn't result in a panic. For the latter, look no further than the play
Rosencrantz and Guildenstern are Dead. At one point in the play, one of the characters suddenly looks out to the audience and yells "Fire!" When asked why, he says he's just "demonstrating the misuse of free speech."
I've never heard of an audience panicking during that part of the play.
-- A2SG, was in that play for a class in college, and did that scene...no one panicked....I try not to take that as a reflection of my acting abilities......