Well, look at it this way. First of all, someone who is vaccinated having "horrible reactions" is very rare, I know of nobody, including myself and my husband who had more than mild side effects which is a normal reaction from the immune system. In fact, my husband had no side effects at all with the J&J vaccine.
We both intend to get our booster shots and are glad to have a life saving vaccine available during a deadly worldwide pandemic. If I have a horrible reaction, it will affect only me.
This is now the pandemic of the unvaccinated. It is the unvaccinated who are overflowing our hospitals, affecting the health and well being of our medical workers, and dying in hospitals hooked up to ventilators. Unvaccinated people are most likely to spread the virus to others and make opening up and living normally much harder to do.
Vaccine mandates for employment is the wise thing to do, since there are so many irresponsible people around. If they get the vaccine to keep their job, it may also save their lives in the end. The majority of dead Americans, over 700,000 were unvaccinated.
My taking the vaccine does not affect you or other citizens in a negative way. Your refusing to take the vaccine affects your community, neighbors and our country as a whole. The only valid reason someone should not get the vaccine is a medical reason from their doctor, allergy to ingredients, etc. Many who can't take the COVID19 vaccine also can't take other vaccines either.