And it's shameful to be sued but not shameful to file obviously frivolous lawsuits, or at the very least being the subject of a frivolous lawsuit would imply no shaming?
Note that I'm not sure what the actual contract terms were in those cases in the article. I suspect it's a guarantor thing. It's very very common to have parents or relatives signed, even if you're an adult.
And I also assume that who actually filed a lawsuit was the property managing company, and some of those companies doesn't care much about reputation. When the issue is between individuals, it's not as common to take it to the court as in US.
https://www.reddit.com/r/todayilearned/comments/1khj2n/til_i...
So I can definitely see how this makes perfect sense when it comes to doing "damage" to apartments (even if only due to reputation / superstition) if there are direct guarantors, but as the news about JR show there must be something deeper going on here.
If family members aren't guarantors, then there's technically no legal ground for landlords to sue the family members. But just being sued is a big stigma in Japan. If the family member has certain social position there's a strong incentive to avoid being sued, or to settle it asap if they are actually sued.