There is no liability because the government is the only untouchable entity there is.
Everyone has to provide products and services that first and foremost don’t harm people, either by design or even by negligence or accidents in this day and age of civil litigiousness. Function and effectiveness is always important, but never most important.
So you can take malicious intent out and sound a hell of a lot conspiratorial, but the whole process of “vaccinating” entire populations in a manor with zero accountability is a disaster, and I have no doubt that there would be a cover-up of any problems regardless of who is to blame and how bad it is.
Private companies forcing the vax HOWEVER are not exempt from liability, and I think most companies are PRAYING they don’t have to enforce this!!