But Superman does exist on this show, and they wrote a crisis that would be worthy of his attention.
That's a chip on the shoulder of Supergirl, which in the context of the show, she shouldn't have. And clearly, since she got her clock cleaned, she did need help.
That was the worst writing of the series--having Supergirl beat him and then making Superman look even weaker by having him run around saying it was fair and square. Let's also not forget that after the fight was over, Kara collapsed herself and was KO'd. She was done too. But even if you buy into the nonsense that Supergirl could beat Superman, which could only happen with weak writing, Superman could turn the tide in her favor, and her ego could set loose Reign on the world, which Superman would have to deal with anyway.
Or an in show explanation why he isn't there.
True, but that battle wasn't so short that it wouldn't make the news, and Clark does have a TV, unless he's chilling with Lois in the Fortress getting some.
True, but they knew a big battle was coming and a Kryptonian was involved. Someone might have suggested to let Superman know about it. No one did.
Yeah--and Reverse Flash laughed it off.
That was a weakness of not having Superman in the first season, or maybe say he was dealing with some of them in Metropolis might have been a good idea.
Let's also not forget that they are changing history on the show by having Supergirl, not Superman, be the inspiration of Legion.