They feel the same way when they propel a mosaic-censored tank to #1 ranking on FANZA when a much less censored black bars version is readily available on the bookshelves of their stores - most people just don't care. And the ones that do care, generally just suffer silently and accept things as they are. Japanese overall are not the most vocal fighters against shitty consumer practices or unfair treatment.
Imagine having to deprive yourself of the manga you've been waiting for, albeit a shittier version, in order to send a message. Or imagine actually trying to overturn Article 175, what if someone sees me protesting and thinks I'm a dirty hentai with no girlfriend.
Anyway, it will be decades before Japan abolishes porn censorship, if it will ever happen at all.