He should not only be ostracized by the community, he should probably face charges. To be charged under the CFAA in America we need only show that he was authorized only to access a certain part of the system and the he exceeded the amount of access granted. He very clearly did that. Users trusted him enough to run his code, and he betrayed that trust to make some political point.

Whether it was via prompt injection or SQL injection is irrelevant. Whether you agree with his politics or not is irrelevant. All that matters is he wasn't authorized to delete code from your system, and he abused the level of access granted to him to do that anyhow.