It's not negative commentary. It is a legitimate user interface issue that several people experienced. It is also super easy for them to fix. Sometimes(always) when you launch a new product or design, you want feedback on the silly little things you wouldn't have thought of that could potentially turn people away. The attention span of cold clicks is measured in seconds. Any silly issue can push someone to click off. I have used a computer extensively for many years and thought it was a live demo for a few seconds. As they say in web usability, don't make people think.
The dramatic hyperbole drives it from being "surfacing an issue" to negative bashing.
"Did anybody else spend half a minute trying to interact with the "app", then give up and close the tab, thinking it was broken before coming back here to discover that it was just a full-page screenshot of a desktop app?"
xauronx, and the majority of the other folks explaining the issue, took a much more reasonable approach—"it was a .5 second instinct to interact with it and then I figured it out. Not sure if that constitutes a negative UI experience or not, but it IS an issue. "
It's just unbelievable to think that anyone familiar with a web interface would get so confused by the screenshot that their only recourse would be to abandon ship.
