I can think of multiple cases.

1. Adversarial models. For example, you might want a model that generates "bad" scenarios to validate that your other model rejects them. The first model obviously can't be morally constrained.

2. Models used in an "offensive" way that is "good". I write exploits (often classified as weapons by LLMs) so that I can prove security issues so that I can fix them properly. It's already quite a pain in the ass to use LLMs that are censored for this, but I'm a good guy.