That's still way too low. A window size of 64KB will be a bottleneck on any 10 Gbps Ethernet connection, except perhaps a point-to-point cable. Any real-world network with switches, routers, and firewalls will require on the order of 256-512KB window sizes for decent performance. You need megabytes for any link that leaves the building!

For reference, 64KB was the default in Windows 2000-XP, and is dynamically raised up to 2MB in Vista and later, and up to 16MB on recent Windows Server versions.

Perhaps to avoid support tickets for people with equipment that doesn't properly support window scaling. The 64k setting is as high as you can go and avoid that.

What planet are you from where there is still such as unique and special flower that talks to only NetApp and no other operating system made in the last twenty years?

The planet where cheap or old or buggy routers, VPN software, etc don't properly support tcp window scaling: https://en.wikipedia.org/wiki/TCP_window_scale_option

I didn't say anything like what you're describing. Also not a fan of your unnecessary cheap shot.