Why don't First Aid/Bandages stop bleeding?

If crudely-cut cotton rags can stem a lethal flow of blood but professional-grade medical equipment can’t, the world of Cataclysm must’ve had the worst health services ever.
It’s not that rags are hard to find or anything, it just doesn’t make any sense. If the ad-hoc solution can solve the problem, why can’t the specialized solution do the same?

You need to select the ‘stop bleeding’ option when you use bandages or first aid.

If someone’s bleeding and they use a first aid/bandage, shouldn’t it be automatic? When would anyone want to heal themselves without healing the wound that’s going to kill them?

It’s because of the way it’s written at the moment. Improvements are planned.

if you have neither or are feeling cheap, also a)pply a rag, works for me

In my opinion a first aid pack should act as a container, containing a set amount of medical equipment, so you could use up some bandages without throwing away some actual healing equipment.

That would be interesting, maybe add some morphine to the packs so we got more stuff to jam into our systems.

And with that being said, a more defined container system would be nice too. Being able to define in what item you put your loot, so you can quickly shed weight by dropping loot filled backpacks for some melee combat.

Nah, first aid kits in the US don’t contain anything like morphine because anything from codeine on up is a controlled substance.