News recently broke that the founder of Japan’s major content site FC2 was arrested at Kansai International Airport. It appears to be related to allegations of distributing obscene videos. He had been internationally wanted since 2013, meaning he had been on the run for 13 years. It seems he obtained a green card and traveled around the world, but in the end, he was caught.

This news has been quite a topic within Japan’s online community, but there’s also a reason it has drawn attention in the crypto industry. That reason is a long-standing yet continually resurfacing debate called the “Tool Guilty Theory.” The issue is that even though FC2 is merely a platform, the question has come up as to whether its founder should be arrested. In fact, in the past, there were apparently people who tried to avoid leaving records when purchasing points on FC2 and instead asked others to make proxy purchases using cryptocurrency. In other words, there was also an aspect in which virtual currency was used as a payment method for uncensored content.

This brings to mind the Tornado Cash incident. The creators of the mixing tool were prosecuted, and one of them was sentenced to 64 months of imprisonment. Even though the protocol itself is a neutral tool, the developers were found guilty because North Korean hackers used it for money laundering.

Reactions among Japanese internet users are polarized. One side criticizes the police for responding too slowly, while the other questions, “Would the person who manufactured guns be found more guilty than the person who committed murder with a gun?” In other words, this is a fundamental issue of whether tool developers should be held responsible even for the users’ illegal conduct.

This debate also calls to mind the Winny case from the 2000s—when the developers of P2P software were arrested because it was used for copyright infringement. The concern is that the same mistake might be happening again.

FC2 itself was established in 1999 and operates as a site for sharing videos, images, and text. In 2013, it ranked third in Japan by number of users, and it also handled domain sales and app development. However, because its headquarters are in the United States, it was operating in a legal gray zone where Japanese laws had limited reach. That’s why copyright infringement and uncensored content were able to go unchecked.

With this arrest, discussions are reigniting about what will happen to uncensored content and how far the responsibility of tool developers extends. This isn’t just someone else’s problem, even for the crypto industry. The question of how much responsibility open-source developers should bear could significantly affect future regulations.