I didn't criticize either your article or your comment :). I enjoyed reading the article and finally learning why it's called godan and ichidan, and it was fun to learn that kau was originally kawu.
Any mention of Japanese learning always brings out negativity and criticism (and the effect is probably doubled by being on HackerNews) so I understand that you're on defense.
My comment was really just an objection to "You still have to learn that and understand that", as I don't think studying grammar is a mandatory step in learning a language (I'm a subscriber to the Input Hypothesis by Stephen Krashen). Though it could very well be that grammar study is an effective shortcut to internalizing grammar. At the end of the day, the amount of hours spent learning from context matters way more than the specific steps taken along the way.
Ah, I see what you mean. For me personally, knowing the shape of the system underneath has a sort of calming effect because I have a sense of the upper bound of how annoying it will be to learn by osmosis. And it's also nice to have a fallback for when I have a cache miss and need to really think through saying something.