Cap is definitely iconic; people know the look and have a concept of what "Captain America" is, though this is actually somewhat problematic when selling the character/film (particularly outside the US), since perceptions of Cap are heavily linked to how you perceive America. The general public's image of Cap is a guy obnoxiously chanting "U-S-A!" and waving a "Four More Years of Bush" sign.
This is not only unfair but untrue. Your first part is right. Cap is seen as a figure who unapologetically chants "U-S-A!". He does so REGARDELESS
of who the POTUS is, REGARDLESS
You only demonstrate YOUR bias with your second untrue statement.
Captain America is apolitical.