It's hard to summ it up shortly and english is not my native language but I try. The message of the movie is basically if your dumb as shit and you obey everything and question nothing you can make it in america. The arc of the movie, the thing with the chocolate box implys that there is something like fate and you can't do anything about it. This may be true on an individual and emotional basis but becomes just tremendously wrong if you mix it with politics. Think about the people in Vietnam or all the boats that shipwreck in the storm when Forrest has his crab fishing boat. Imagine telling these people: Yeah, you just got the wrong chocolate, sorry. Also the people makes jokes about everyone who was against the Vietnam War. The black panthers are sexually assaulting Jenny and all the hippies just seem like a bunch of idiots with no clue about the world. Jenny's character is also particularly interesting, because she refuses to life a conventional live and gets punished with aids (think about the chocolate box again). Meanwhile forest just doesn't question any of the events happening around him and then there's one crucial moment at the memorial speech where he could say something and take a position and the film mutes him. Basically this film tells you that you can't change the circumstances you're in, that life just tosses you around. In reality it's not life which tosses you around, it's governments and a political system which does (regarding circumstances in the movie). Of course if you get in a car accident and die its not the system, but if you're going Vietnam it is. A counterargument is often (as always) that you shouldn't overpoliticise movies but in this case the movie makes itself extremely political by traveling to American history and its political events. Anyway, there are no unpolitical movies at all in my opinion. Don't know if I could help you.