I don't really agree with the if a hand is <-100bb/100 you shouldn't play it from the BB argument.

If we play hand A from the BB and we win at -80bb/100 and we always fold hand B (-100bb/100) then our average from these two hands is -90bb/100.

If we play A and B from the BB and we win at -50bb/100 w/A and -110bb/100 w/B. Then overall the average of these two hands is -80bb/100.

Which is more +EV?