I can sort of see why? Cat's classic take can be somewhat annoying in the wrong hands, especially to modern audiences who are sick of love triangles. And her Ann Coulter turn in the 2000s wasn't much better. The Supergirl show was arguably the best modern reinvention of her.
I should also point out that Smallville had two Cat Grants.
https://smallville.fandom.com/wiki/Catherine_Grant
https://smallville.fandom.com/wiki/Cat_Grant
That's not the only time Smallville did this thing of splitting two characters of the same name. They did it when they revealed that the Jimmy Olsen who died also had a brother named Jimmy and the show technically had two adaptations of Supergirl.