I love this essay, but I'm conflicted about this specific example. It doesn't even occur to us to think twice about "all and only" the male superheroes lined up and fighting. The female superheroes jump out partly by being different than the male default and partly because of the social context you mention. It's not necessarily unrealistic in the MCU, and it can't help but be perceived as political due to the social context. With that said, I can certaily see the point that it might have been more intertwined with the story, perhaps if the men had happened to be occupied somehow right before or if the "she's not alone" line had been axed.