Once upon a time there were people. And then there were children and Judaism. After a few generations, a wise rabbi noticed that some adults are bad people, like murderers or pagans, and others were good people, like fellow rabbis, blacksmiths, or moneylenders.
And he noticed that as young children he couldn't see any critical difference in people. He couldn't predict who would turn out good, and who would turn out bad. He guessed that whether a child would be a good or bad person as an adult was not yet determined when they were still a child.
He tried preaching to people. He told them about how to be good people. He found very little success preaching to bad adults, but he found that in a controlled, double blind study the children he preached to turned out to be good adults at a much higher rate than children in a pagan control group.
And thus our Rabbi determined that human actions play a role in whether children grow up to be virtuous or wicked. But he wanted to help everyone, and some of the children he helped still turned out badly. What was going on? He needed an explanation.
He came up with the explanation that it is within a person's power to turn out either way, and they are able to choose which way they want to be. He found that the world made more sense taking into account this explanation. He found the explanation helped him and did not create any worse problems than he had before. He concluded that the explanation, while it may not be perfect, had content. There was something good about it.
Over the generations the idea of free will was refined. For example, people noticed that adults sometimes can make choices and change themselves. And they noticed that people get more than one choice in their whole life. And they noticed that the concept can be applied to simple things like "choosing" a flavor of ice cream. They also noticed that it sometimes may not apply; they noticed factors that can make it hard to choose; and they noticed factors that reliably make most exposed people turn out in a certain way.
Eventually, by the year 2008, the general understanding of free will was quite a bit better than the original, including the understanding of what is and is not an exception. Progress had been made.
If someone wants to say that free will is a bad concept, he needs to tell a better story. He needs to solve the same problems in a better way. If he wants to replace this story with nothing at all, that is a revolutionary, anti-Popperian approach which is inconsistent with the steady growth of knowledge. We need improved ideas that do a better job of solving our problems. We don't need a bunch of logicians to go on a rampage throwing out any ideas they don't understand well enough to justify, and leaving us to find new solutions from scratch.