That is not the case in 4chan. There are a large number, if not a majority, of boards which have healthy, constructive cultures and are extremely helpful for hobbyists and enthusiasts.
i had great discussions on /sp/ when the world cup was on. same with nfl games.
While I disagree that 4chan is "toxic" in many ways it is representative of society in the way that twitter represents a fleeting incomplete thought.
What you have said maps near perfectly to the state of America. While politicians have totally fucked up the country, it is somewhat bleeakly obvious that these same dynamics are at play here.
So if you are American consider that you are in a physical community where the loudest, and most controversial members are making it a terrible experience for people and that they have chosen leaders that mirror their own desire to * refuse to deal with it, which unfortunately leaves us with the unpleasant assessment is that the community is toxic