I'd love to know how you plan to do user mode packet filtering. Keep in mind that on Linux, the designated API is inherently kernel mode. https://netfilter.org/

This isn't one of the cases where we're talking about Linux being superior to windows. Any OS will be fucked if you give it a mangled kernel module. In this case, it's just that only one got one.

Your perception that anything that touches the kernel is an intrinsic security risk is unfounded.