It's not about you.
I'm not convinced that boosters should be required, in order to go back to work. But, really, to answer your question: It's not about you. It's about the people you're around. At work.
Just like everything else with COVID -- the reality is that we have to account for the affect on everyone, and not just ourselves. Individually, we have extremely low odds of suffering the worst from COVID. Collectively, hospitals have overflowed, 700,000+ people in the States have died, and many are suffering long-term health consequences.
It's not about you. It's about everyone.
That being said: I'm in Canada, where boosters are still uncommon. I've never heard of any booster requirements, just to go into the office.