"Why are we introducing Spider-Man in a movie named Captain America: Civil War?" is a question that SOMEONE at Marvel should have asked.
The MCU in general is becoming increasing overstuffed with every new entry, I liked that in Phase 2, each movie was specifically about the Marvel superhero in the title. We're now at the point where every film is basically an Avengers film, where everybody appears anyways for no apparent reason. I forgive Civil War to some extent because the original source material was a huge crossover event but really, when you're introducing new and unrelated characters like Spider-Man in what is supposed to be the concluding film of an overall trilogy and arc concerning Captain America you should be stepping back and asking, "Why are we doing this again?"
So first people wanna complain when there are no other heroes in these movies, but now they do it people also wanna complain? Aight. You can miss me with that shit.