>> what people are sending to Claude that is so secret

Its the same point used against privacy. What's so secret you are doing that you need privacy. I think in the end, its about privacy and not trusting these model companies with your data. Facebook manipulated people behaviors with all the data they had, no reason AI companies wont someday decide to do that same, and they have far more intimate knowledge.

When it comes to coding, I also don't like the idea of them taking my money and potentially at same time potentially using as dataset generator.