Well you can say the same for European countries especially the mental giants who have a tattoo on their neck hand face or any other
bodypart that you cannot cover up.
Yes, that's pretty stupid.
But in Japan, having a tattoo would limit your social life a lot, even if it is on your arm, if it shows, you might be thrown out of any public place, even restaurants, zoos, whatever.
No pool, no hot spring, no sauna....