So, regardless of what else you ask in the interview, this question makes the interview two-way instead of one-way

No it doesn't - there's nothing in the article about asking for feedback in return. The only reference to somebody actually doing that is extremely negative.

If the author reads this, they may be well-motivated but should consider quite seriously that they are not understanding "two-way" as they intend.

Author here. That's a fair point. Interviews will never be fully two-way. The intent of the point is to allow them to correct misunderstanding I as the interviewer may have (making it slightly better than me going away with an incorrect interpretation). Interestingly quite often candidates will give me feedback on the interview process as well.

But you are right. Interviews will never be fully equal.