I agree with that, subject to the assumption that your CSPRNG is built on CS-enough primitives. (What I disagreed with is the argument made by the GP, not you,

I agree with that, subject to the assumption that your CSPRNG is built on CS-enough primitives. (What I disagreed with is the argument made by the GP, not you, that the Linux entropy value was incompatible with their in-principle mathematical description of "true" entropy. Pretty irrelevant to real cryptography.)