Why is bacterial meningitis worse than viral meningitis?

Bacterial kills!!: In most cases viral meningitis is mild and the body itself takes care of this. There are exceptions, such as herpez meningitis... Bacterial meningitis is always serious and fatal in most cases if untreated.

Many reasons: Bacterial menningitis usually results in pus in the meninges which causes damage it also affects the blood vessels which can cause strokes.

Nature of the germ: In the same way a bite from a grizzly bear is worse than that of a kitten, bacteria tend to be more destructive than most viruses. There are some viruses, like herpes simplex, that can be as destructive as the usual bacterial meningitis,pneumococcus or meningococcus. Most viral meningitis starts out with common intestinal viruses that produce a few symptoms for a while and self heal without injury

Nature: Viral meningitis is usually relatively mild and self-limiting. Bacterial meningitis is quite severe, damaging to tissues and progressive unless treated effectively with antibiotics.

Bacteria more: Destructive. This is a difference in the biology of the pathogenicity of bacteria vs. Viruses. Bacteria induce stronger inflammatory response, release more toxins, enzymes etc.