@Archivist I didn't write that, but it is the case that many people who sell software don't follow license terms anyway.

When it comes to proprietary licenses, respecting the license terms to not share and betray humanity is immoral, but not respecting the terms may be illegal - so to be morally pure and also follow the law, one must avoid ever agreeing to a proprietary license.

The GPLv3 gives permission to do everything you would want to do with software, except the immoral act of restricting the freedom, so it is trivial to be moral and also not infringe the terms of the GPLv3.