Of the six, 2 were Unitarian ministers, 1 was a teacher, 1 a journalist and 2 business men.
By your count - which I don't dispute - it was not just wealthy industrialists that wanted to violently attack the South in cross-border murder raids.
Your point is well-taken: a cross section of the North was willing to fund and support murder raids. Then, as now, many people defended what was done and contend there was nothing unconstitutional or wrong with the John Brown attack.