Traffic in general can be (roughly) summarized as application, infrastructure, and signaling. On top of this, it's clear that different address space is used by

Traffic in general can be (roughly) summarized as application, infrastructure, and signaling. On top of this, it's clear that different address space is used by different organizations for different purposes. Classify the traffic based on these differences and carve up address space to suit the differences, and perhaps differences in the transport protocols that match the practical differences in how the traffic is used. For example, bgp traffic shouldn't work on non-routers. Certain signaling (icmp and udp traffic flags for non-peer traffic) isn't needed by most customer equipment. And it's stupid that IP spoofing works at all, much less on robust servers on internet backbones. It's clear there is traffic allowed on parts of the internet it shouldn't be allowed on. Changes could be made to correct this, and no, they are not political.