Comics Gen Superman

His point is one I often consider myself. Of course one drops it because it's comic books, but it also makes some sense. Consider this.

Green lantern has a ring with a technology that is completely outside of our comprehension. It's part of the premise, so we accept it, like in any science fiction.

Superman is an alien whose physiology is unique. It's the premise, so he can fly, is super strong and can shoot beams out of his eyes. We can accept it because it's the premise.

But travelling at the speed of light is something of which we know the consequences. It would cause a massive time-space local distortion and the annihilation of matter in that spot, with an energy release that would be catastrophic.
Now, if the premise was that Superman travels faster than light without actually traveling, but like teleporting or distorting space-time, then we may accept it.

I don't know if I was clear enough.

Mind you, I'm not saying that it is bad writing. I, like you, think that in superhero comics actual science should be left out the door. But there is a substantial difference between creating something sci-fi that does great stuff, and another to ignore laws that are there without an actual justification.