The line length range, 25-to-70 has been a weak point of the rules for decades.
It should have a more reasonable and better-thought-out set of ranges, not just 25-to-70 across the board.
Perhaps somthing like:
1/2A: 25' to 52'
.050 to .25: 42' to 70'
.26 to .4028; 52' to 70'
above .4028; 60' to 70'
The writer was correct, the rules do permit flying on extremely short lines, which would be unsafe if anybody did it. But I have yet to see anybody try it.