Why remove IRQF_SAMPLE_RANDOM if "it cannot make the RNG output worse."
We should not care if network traffic can be sniffed in some configurations
(plus sniffing could be very unlikely in some others).

It makes it much worse - it lies about entropy.

My understanding of openssl developper answer is same as yours :
"it cannot make the RNG output worse."

If you don't care about the quality of your "random" numbers then
use /dev/urandom. It's very simple.