While there is a degree of maturity, I feel that over all there is a sense of family friendliness. There's a rating for a reason, and while it's debatable, I don't actually think it's that big of a concern. Maybe Guardians 2 pushed it a bit, but I dunno.
And I also wouldn't call any of the movies stupid. DC, I can easily say parts of those movies are ridiculously dumb (i.e Martha) but I don't know about Marvel films.