The only thing they make is food, They would'nt poison anything because they would not only kill them, But their family.
Striking fear to enforce they don't [censored] around.
The reason they can't get an Howitzer to work, Is because the FIRING mechanism is missing.
You realize you need that right?
I'll give you that we have not seen Slaves make weapons but we have seen them make pretty much everything else.
Legion can't get the Howitzer to work because the Firing mechanism is missing yes but do you know how NCR would fix it? They would make a NEW firing mechanism or better yet make a whole new Howitzer. Would take time to move it all the way from the West to the Dam but they could do it.
History lets us know that Slave Labour is not the best labour you can get. They always rebel and if they are making your food and medicine that just leavse you that much more vulnerable. The death of Caesar could give the slaves the chance they need to rebel.