It was clear that the initial statement from the US state dep. was meant as a jab and yet people here argued against that ferociously for some reason.

Just because it was clearly interpreted to be a jab by Erdogan, it doesn't mean it clearly was a jab. All it asked for was confirmation of the cause of death, which isn't unreasonable considering the US would have been monitoring Turkish Armed Forces bomb the site for four days before attempting a hostage rescue. Atypical behaviour for a hostage rescue. This article the sparked the conversation confirms this:

The wording was interpreted by Ankara as lending credence to PKK claims that Turkish forces are to blame for the deaths, and prompted a fierce reaction from Turkish President Recep Tayyip Erdogan.

In the interim between the first (still unamended) and second statement, either the US State Department decided to clarify to appease Erdogan, or perhaps were privy to evidence, we don't know.