We did see both sides of the public reaction. The anti-alien side was focused on because stories are driven by problems and dangers, but we also saw pro-alien protestors standing against them, we saw the pro-alien march and the events that shifted public opinion more positively, etc. No more insane than a lot of the current administration postings in real life. It's only a few steps from what ICE is doing to immigrants right now to what Ben Lockwood was doing in the show. The point of cautionary tales in speculative fiction is to go further than things have already gone, to warn us how much worse they can get. Back in 2014, Pocket Books published a Star Trek novel miniseries called The Fall, in which a corrupt president took over and tried to turn the Federation and Starfleet down a darker path, and I found it unbelievable at the time how quickly and effectively he managed to take power and shift the Federation's democracy in a more authoritarian direction, especially given that he turned out to be a fraud complicit in the crimes that made it possible for him to seize power. Two years later, I realized it had been prophetic. Sometimes, what seems insane and impossible in the present ends up becoming reality surprisingly quickly. Frankly, if people are already that far gone, then no work of fiction is going to change their minds. Hell, people like that probably aren't going to be watching Supergirl to begin with, or much of anything on The CW. The targets are the people who are still subject to being swayed, particularly younger people not yet set in their views. And again, telling good stories with well-drawn characters comes first. It is misunderstanding fiction to think that political messages are its exclusive priority.