Not true. AT&T claimed that the free versions of BSD violated their copyright on Unix with the result that even though anyone could download and install BSD at no cost, you never knew whether a court ruling would make your continuing to use it legally risky (at least if you want to use it in an enterprise or keep it connected to the net).
The legality of the free versions of BSD did not get resolved till there were many Linux users -- probably more Linux users than there were users of the free BSDs.
BSD had already done that, better, and earlier. Let's not try to rewrite history.