It's less exciting then that. It wasn't clear it was the sole reason, an influence, or coincidence. There have been quite a few businesses using their right to fire a person over comments made about Charlie Kirk, and those came about without FCC bullishness. Even if this was done off hours, at home, on their own personal Facebook page (or their social media of choice), you do continuously represent the company you work for; and they may frown if your choice of words causes an impact to their bottom line. This isn't an attack on free speech; this example with Jimmy was blatant lying. No one on the right should contest the ability to state freely on social media, their love of death for Charlie Kirk, however vile. It reveals their lack of humanity clearly, but they have that right.You're clearly ignoring or ignorant of FCC Chairman Brendan Carr's part and influence in this entire topic. Directly violating the First Amendment.
However...businesses have the right to find your speech problematic to their bottom line and terminate your employment; even if off hours. Having a difference of opinion on topics is different than reaching into the pram and pulling out anti-human statements. They are both, certainly, free speech. One engages in discourse; the other, a statement on their character. That point can hardly be debated.
I'm thankful companies are, even if for their own optics, terminating employment of people who will champion the death of others, even celebrating it. This disturbing behavior shouldn't be tolerated (my opinion) in a civilized society. But, they should have a right to say it; no well adjusted person on the right would or should deny that.