So often, a particular strategy becomes dogma. Copyleft licensing constantly allures us in this manner. Every long-term software freedom advocate I have ever known — myself included — has spent periods of time slipping on the comfortable shoes of belief that copyleft is the central catalyst for software freedom.
Copyleft indeed remains a successful strategy in maximizing software freedom because it backs up a community consensus on software sharing with the protection of the law. However, most people do not comply with the GPL merely because they fear the consequences of copyright infringement. Rather, they comply for altruistic reasons: because it advances their own freedom and the freedom of the people around them.