[weikju]

I think on its own the sentence is fine. However, in the cultural context of tech discussions on the Internet, "why don't you just [X]" is usually passive-aggressive or an indication the person asking this hasn't taken the time to consider the use-case or constraints, and might even insultingly belittle the person for not having considered such a "straightforward" "easy" solution.

I myself balk at the sentence all the time, and I have nearly stopped using it in any communication because it doesn't communicate the right thing.