How? What exactly would a reader be "mislead" to believe
The part about "inherently sinister" seems to be a thought from the mind of an HN commenter not the authors of the submitted web page. The later only describe LinkedIn's actions as illegal, not "sinister". The laws cited by the authors do not appear to consider any "state of mind", e.g., "sinister", or intent as relevant
"But I do take some issue with the alarmist framing of what's going on."
AFAICT, the submitted web page does not suggest that anything LinkedIn does is "dangerous", i.e., cause for "alarm". What it suggests is that LinkedIn's actions _violate European privacy laws_. The authors claim LinkedIn's actions present an opportunity to enforce these laws, i.e., "take action"