>It always troubled me that there was so much vitriol for Maisel from the exact same community of people who rightly insist that free software licences are enforceable and that non-compliance should be shamed.

That community is generally opposed to copyright and intellectual property altogether. Copyleft is just a hack to create a space where it doesn't exist. If I could "infringe" on others without being punished, there would be no need for copyleft enforcement. That's the idea, anyway.