I see a lot of people complaining about the scrolling thing but I don't get why, can someone explain?

Many HN users are always looking for an excuse to complain about the format or appearance of the linked sites. So much so that the following had to be added to the guidelines (but doesn't seem to be enforced that much):

> Please don't complain about tangential annoyances—e.g. article or website formats, name collisions, or back-button breakage. They're too common to be interesting.

https://news.ycombinator.com/newsguidelines.html

Because we're used to speed-reading content and that website wouldn't allow us.