A lone shooter in the town of Vernheim, in the state of Hessen, Germany, was killed after a short-lived standoff with police.
"It remains unclear whether the shooter's motives were ideological, personal, or whether he was simply mentally disturbed."
"Ideological," "personal," and "mentally disturbed" are not mutually exclusive motives.
In fact, they usually exist together.
The desire to "explain" and "understand" is understandable. But "finding the motive" can simplify the complex, synergistic "drives" that motivate human actions.
The frame of "find the motive" also locates "the motive" inside the mass shooter, and avoids more complex understanding of social forces that shape human motivations.