If his position was not substantively very negative, then it was not correct to represent position as very negative. (Even if he was waiting for an asset to settle, that has a positive value that should have canceled out any negative.)
The fact that it's "normal convention" to represent positions this way is a problem with the convention, not with retail investors.
The fact that it's "normal convention" to represent positions this way is a problem with the convention, not with retail investors.