Exactly. There are good arguments to be made about how secret identities are dramatically or metaphorically interesting, but arguments in their favor on the basis that it's more realistic don't hold much meaning for me.
I thought it was the arguments
against secret identities that were more realistic. Realistically, disguises are rarely that convincing, especially to people who know you well. Realistically, surveillance, facial recognition, and forensic science are at the point where it would be very hard to keep anyone's identity secret from the authorities. Realistically, you put people in more danger by hiding things from them, not less. Realistically, lying and tricking your loved ones and controlling their access to information about you is a form of abuse, not love.
Does anyone actually care about that level of realism?
There's always room for realism in fantasy stories, as long as you keep in mind what "realism" actually means. It doesn't mean an exact recreation of reality; it means an artistic style that conveys the
impression of reality, which isn't at all the same thing as actually being real. It's like the old joke: "The key is sincerity. If you can fake that, you've got it made."
Realism is not so much about conforming your fiction to the limits and problems your characters would face in reality as it is about
acknowledging those limits, nodding to them to give your story a plausible texture while you work around them. Since what you're doing is still fiction, it still needs to play out as an entertaining story and thus have certain unrealities to its structure. The surface layer of realism just helps mask that artificiality and sell the illusion. It's like writing hard science fiction -- if you acknowledge enough real science in explaining the fanciful stuff, it helps sell the illusion that it could actually work. Not enough to hold up to a real scientific analysis, of course, but enough to
feel believable in the moment so that the audience is willing to suspend disbelief until afterward. The facade of reality is convincing enough that you have to go back afterward and dig deeper to find the artifice.