Have you seen a japanese newspaper? the characters alone are very information dense. and a newspaper front page can be very information dense just by the nature of the language/writing system.
otherwise, a lot of japanese webpages just seem impossible to navigate to me. Some images are clickable, some aren't, you still have to scroll to reach where you're going. It's just a bit like a maze, and a lot of what you see is kind of useless.
To be fair, Japanese headlines use a specific writing style that is much more compressed than normal text, like how English newspaper headlines drop words like “a” or “is” to save space.