why are they making people sign a waiver of responsibility when they take the vaccine when there is a fund for people who are harmed?

Such waivers are an attempt to limit exposure and liability.   Typically this is the process waivers go through:

1 - psychological:  whomever you signed the waiver for hopes, if you have a problem, that you recall signing a waiver and never file a claim - "because I signed a waiver."

2 - intimidation:  if you start making noises about an issue, they put the signed copy of the waiver in front of you and say "why are we even having this conversation? - you signed this waiver."

3 - legal leverage:  if a claim blossoms into a suit - they hope the signed waiver gives them leverage towards dismissal or mitigation to lessen fiscal exposure.

The waiver protects the facility and the person injecting you.

In theory it prevents the "patient" from suing the person who "provides" the medical service, i.e., the Pharmacist/Tech/Nurse/Physician who gives the shot.  You cannot waive your legal rights, so it's pretty much meaningless.  I'm sure SOMEONE is going to sue one of the drug manufacturers for something.

That is generally standard practice for all medical procedures and treatment.