I had a mentor in the past whom I met again after 10 years. A philosophy professor. He told me something about free will: there are several kinds of people. Those with enormous volition that use their willpower to do either good things or bad things; and there are people with scarce volition who are too scared to use their own free will, for they don't want to commit mistakes. There are so many shades of individualistic cases inbetween.
He also told me that free will deniers are usually people with a big volition who use their prepotency to destroy other people's lives.
They deny free will exists because admitting it does exist would make them feel guilty of all that they have done unto others.
It's a self-defense mechanism not to feel guilty.
What do you think, guys?