In answer to the question, I suggest that they have. Materialist philosophy inevitably leads to transparent absurdities and self-contradiction, whether moral relativism (a truth claim about morality that no truth claims about morality are valid), or that random errors can produce sophisticated information-processing technology (for which there is no evidence and much disconfirming evidence).
The no-free-will thing is yet further evidence of the lobotomizing influence of materialist philosophy. Just the other day I was in the supermarket, and decided to treat myself to some ice cream. I like the Haagen-Dazs coffee and dark chocolate varieties. I thought to myself, “Self, which flavor would you like to purchase?” I chose the dark chocolate.
A thoroughgoing materialist would argue that my choice was no choice at all, that my decision was determined by my brain chemistry and other such transparent idiocy.
I make free-will decisions all day long every day, just as everyone reading this post does.
The denial of this obvious fact, along with other absurdities and self-contradictions as mentioned above, leads me to conclude that materialists have indeed lost their minds.