Actually they edited it out. Look at the writing it is just a translation and multiple drafts were written edited written edited written and edited...
A lot of these individuals were actually kids. It wasn't a bunch of old men and in fact life expectancy back then was only around 30s.
Luckily they did have an education to see what pure democracy as well as other forms of failed governments they could learn from.
However I'd really like to be a fly on the wall when the conversation about writing these documents with the Iroquois Confederacy was going on...