Why do people believe in free will?

Our brain is biological and biology is governed by the laws of physics. This means that all of our experiences, our thoughts, our decisions, our emotions — all of which derive from processes within our brains — are just as deterministic as the orbits of the planet. There are few physicists and biologists today who still believe in free will and it is becoming increasingly taboo to do so. Some may claim that quantum mechanics implies a degree of uncertainty and randomness, but randomness does not imply free will. (If your thoughts and actions occur randomly, where is the freedom in that?)

So no, free will is an illusion that exists among the masses and yet people cling to it so fiercely. What are they so scared of? Do they think our moral fabric will be disintegrated? That life suddenly will be meaningless? Why do people insist on believing in something that the scientific community is discarding as an illusion?