

Their career is being targeted, their position of being a really influential and highly regarded tenured professor is being targeted. But having this career is not a human rights, it‘s a privilege. And they can use this privilege to protect weaker members of society, like students whose rights are actually threatened.
If Norman Finkelstein is not in danger then they are definitely not in danger.
They could stay at Yale, they could keep writing and doing research to their best conscience, and then make as much noise as possible if someone tries to stop them.
They could help organize, help protest when academic freedoms are being attacked, or anything else, except flee at the slightest bit of resistance.
Bernie Sanders and AOC have shown that there are tens of thousands of people in almost every US city willing to get onto the streets to resist Trump. So they will not be alone, and then if things get really hairy, then they can flee.
And besides that, they are the self-proclaimed fascist experts, so they should be able to think of many more effective strategies to resist authoritarianism. But I doubt any of their proscribed strategies is for the elite to pack their bags at the first inconvenience.