Part of me likes all the insanity with the internet back then, with mixed feelings. I probably got computer skills wasting time on YTMND for one reason or another. I 100% attribute 4chan's b for inspiring me to program. Their raids inspired me to learn programming when I was a teenager. But... I see that the alt-right came out of 4chan and the previously funny memes were no longer funny memes but serious accusations.…
I think you give too much agency to 4chan. It's just a imageboard - an internet forum - that happened to have some subforums related to alt-right. Maybe it had (has) a bad influence on people, but it's hundred times smaller than Facebook, Twitter or Reddit. To say it has single handedly started a movement is a huge stretch.
I disagree. Anonymous was an substantial movement.
4chan has long existed before the concept of facebook and to compare 4chan to the new trends of the likes such as facebook or reddit when 4chan is it's own, you can't.
Reddit and Facebook have all been designed to cater to the masses; 4chan not so.
To rule out that 4chan has never been influential is incorrect.