Many camera bags use to have straps/loops on the bottom for a tripod or monopod. It helped sell the bag. But the monopod on the bottom of the bag never works. It sticks out and pokes people, gets caught in doors and makes it hard to set down without tipping.
For those who want to carry a monopod, I strap it to the shoulder strap! You can tie it on with rope, bungie cord, or some Velcro straps sold in boating/camping stores.
(Long Lens bags come with Velcro loops for monopods.)