"open source backers like Meta’s Yan LeCunn" Though, it's not really that open source.
I'm not surprised that "Closed system companies like OpenAI and Anthropic" would oppose "open sourcing" it. That would open them up to more competition. FB is different here, as they don't make money directly via offering up paid APIs.
A better argument could be made about algorithms which make decisions about people without their consent. The examples here are not that (and tend to be the most cliché and exaggerated ones).