The different boards of 4chan have vastly different cultures. The tech board isn’t much different than what you’d find on Lemmy. It’s filled with Linux and Free Open Source Software geeks who love to interject argue over the finer points of operating systems.
The negative stuff you hear about 4chan almost always stems from the boards that have little to no moderation. The boards with moderation aren’t much different than Reddit or Twitter. Actually, Twitter might be worse nowadays.