Genuinely curious, but do you guys not know how japanese law works when it comes to porn?
Another thing I would note in addition to the post above is that not everyone is a veteran in hentai, there could be newbies starting out.
And not everyone is going to be like
"oh I see so much censored hentai... wth? letme google *googles: why hentai censored*".
So regardless of the rhetorical questions as venting on some posts, I am fairly certain that there are users who have actually no clue.
And even once they learn it they are probably left with "why" because there is a HUGE industry for porn in japan but they have a law that makes it
"less enjoyable" since they made a law VERY long ago and it just continues to be in effect since no one wants to look like "the perv who got rid of censor laws on porn".