Copyright prevents heresy.

Copyright gives you the ability to haul someone before a secular court, but that is not the usual (or biblical) way of dealing with heresy. The apostles had to deal with people manipulating their words (2 Peter 3:16) but they did so by teaching faithfully and rebuking those who maligned them.

There are still other ways of preserving integrity such as with trademarks. For example, the popular Internet browser Firefox is open source and anyone can copy and change it but they can't call any copies "Firefox" or use the logo as they are trademarked. It can be the same with Christian resources and even the Bible as well. Even if a popular translation like the NIV were to allow changes, the name itself could still be trademarked and no one could call any modifications "NIV".

But to rely on the threat of a lawsuit is contrary to Paul's teaching (1 Cor 6:7), who instead encouraged us to wait for the Lord's judgment (Rom 12:19). God will expose the lies people tell and he doesn't need secular courts to ensure his Word is preserved.

Also see the objection regarding forbidding derivatives