Comments to HN need to be civil and substantive. The comment was neither. Here's how I look at it:

"Congratulations on completely not understanding" --> snark and personal swipe—definitely uncivil.

"the entire issue of weight gain and obesity research that's been happening for the last 15 years" --> ok, but just mentioning this isn't the same as saying anything substantive about it.

"You win all the prizes" --> more snark and personal swipe

Civility is most important, so if you'd dropped the first and third bits and kept the second, we wouldn't have chided you. But if you wanted to post a good comment, it could have begun like this:

Obesity research for the last 15 years has shown there's a lot more to this. For example, ... and then add something specific.

Consider how much more polite and specific KirinDave's reply was: https://news.ycombinator.com/item?id=13267354.