Well, even if it's provably suggested that there is no free
  will, nevertheless, UNTIL we have the technology to figure out
  "What so and so was thinking on July 23, 2015 when they killed
  this person and why", a "there is no free will" isn't a
  pragmatic position for any society to hold. If an individual
  wants to hold "there is no free will" as their belief system, I
  don't have much of a problem with it. I tend to go with it this
  way: The appearance of free will, for all practical purposes,
  *is* free will. From a pragmatic standpoint, we have free will.
  Free will is real. Maybe at some point in the far off future
  we'll have the capability to determine what you will be thinking
  about tomorrow at 4:02pm and what you will be doing... but until
  that point, it seems less reasonable to hold a no free will
  position than it does a free will position. Certainly socially
  anyway. Individually? People can believe what they like. One big
  flaw in a no-free-will position is how it's utilized: As in the
  OP, people will sometimes use a "we don't have free will" as an
  excuse for bad behavior that they know perfectly well they
  could've chosen otherwise. A *true* "I had to do it because...."
  [circumstances made it impossible to choose otherwise] I think
  is extremely rare. There are far too many other variables in
  play to determine causation in such a broad area as cognition,
  action, choice. But, I could be wrong. That's just my take on
  it.