This is a form of bias on their part. They think or say it’s being balanced, but the lack of full factual disclosure is a choice. Bias can show up in other ways, too.
The length of a segment, for example. How long a topic is covered shows bias through emphasis or lack of emphasis.
Omission of details, over-covering points of view while ignoring others, when a story is covered, who covers the story, etc., may all seem unimportant, but they are choices.
Bias isn’t necessarily bad if it’s factual. To your point, someone should be stating who this individual was - even just generally - and state something along the lines of what you’re saying to refute the “mentally ill” allegations.