According to the "HN guidelines" [1]

> Otherwise please use the original title, unless it is misleading or linkbait; don't editorialize.

So, "Stop using" could be considered "linkbait", which could be why it was changed to just "Using".

It's ironic that this has the effect of misleading the author's intent...

[1] https://news.ycombinator.com/newsguidelines.html

I noticed this as well; at first I thought this was a tongue-in-cheek response to the "Stop..." version.

I'm not sure - I didn't edit it and I don't know how to fix it

HN has some rules for automatically fixing up headlines. Usually it edits out small words like "the" and "a" at the beginning of a title.

I have no idea what the rationale for this is, especially considering the potential for corrupting the emphasis of the original headline, like in this case.