I flagged this answer as not an answer, and it was declined:
declined - flags should not be used to indicate technical inaccuracies, or an altogether wrong answer
The answer does not answer the question, but adds onto the accepted answer. It does not offer an answer of its own. Without the accepted answer, this answer would make little sense (What is the "IntelliJ idea"?). But, it has the highest amount of up-votes on the question, so the community has deemed it worthy information. I don't know if this was taken into consideration when the moderation addressed the flag, or if I'm misinterpreting what can be considered an answer.
I would have thought in this situation it would be better suited as a comment to the accepted answer since it relies on the accepted answer's information. I would like to know the rationale behind keeping it as an answer, and if the amount of up-votes in an answer has any weight in the decision making process, as long as it makes a positive contribution.