> Anyone else find it strange in the US with the self-insured health care plans (the norm with large companies) your company has complete visibility into every health care interaction you have while employed through claims data?

Self-insured plans means that the companies underwrite their own plans, but they almost never manage their own claims. That would be cost-prohibitive and absurdly disadvantageous. The employer never touches raw claims data at all.

Companies have access to aggregate claims data, but they absolutely do not have "complete visibility into every health care interaction you have while employed".