Batman is meant to be taken spr srsly as being this undefeatable monster that can strongarm (rather than outmanuever) anyone, despite being a normal human; by comparison, squirrel girl is notably strong to begin with, and not meant to be taken seriously, and typically gets by through a luck factor or her friends, rather than "I am badass, hear me roar". :P

She's a far better character than most portrayals of Batman or Superman or Wolverine or so forth;
Though that mostly is an issue of most mainstream comic writers being total hacks that only know how to write "me so strong" characters [nevermind how each time a NOT AAA-class character gets shuffled around to a new writer, they get more and more abused. Poor Gambit.. ].

Take the song Superman by Five for Fighting- now that's the Superman I want to see.
Instead, we get the erratic, thick-headed emo kid from Smallville, and the "I am an iconic symbol, I have no flaws" mainstream comic character.

Of course,mainstream portrayal is one thing- each of the characters have had moments where they've been with writers that have let the characters shine.

Here's Superman at his best.