You said "non-US copyright" and "legal", while the Berne Convention, of which the US is a signatory, states that copyright of any signatory nation extends to all signatory nations as if it were under national copyright in each nation.
So you should care, as he/she was pointing out a false statement in your original post and what you claim to be legal is actually illegal. Whether you change your use of fansub animes is really besides the point.
Some people neither know nor care about the legal situation. If what they want is available legally when they want it they'll get it via that route. And if it isn't they'll just pirate it.
Anime communities are pretty strict in asking people to buy licensed DVDs and to take down torrents for series that receive a US release.
I guess it is. Seems to be meant to protect potential revenues of a local show in the international market for the length of the copyright.
However the flaw is that copyright still doesn't negate the old saying of "strike when the iron is hot" and no copyright length will protect your potential revenue if you don't move fast enough.
I guess I should find another example of non copyright work although even doujinshi which i would argue should be considered original work due to the time and effort of the author are considered illegal since they use copyrighted elements.
Copyright prevents derivative works and stifles creativity. Just look at the UK comic scene all the comics are original works no doujinshi at all and i suspect its because copyright is too strict and you wouldn't get a table if you wanted to sell one the organizers of the event would be afraid of being sued.
So you should care, as he/she was pointing out a false statement in your original post and what you claim to be legal is actually illegal. Whether you change your use of fansub animes is really besides the point.