The author seems to go out of their way to point out the cultural relativism between his own views and Japan, and differentiates between lolicon and child porn. I see no problem with him finding lolicon personally uncomfortable, or with the premise that Americans in general might find it unacceptable, because they very well might. I don't see him condemning it outright.

The article, however, is written in defense of distributed platforms like Mastodon as a way to enable free expression, as well as an attempt to raise the question of how to increase mainstream adoption of tools like it when those tools are primarily known for hosting controversial content. I don't believe the author or the article are as Puritanical as you make them out to be.