I'm not sure when modern tech got this idea that if everyone has been using something "wrong" for decades, it's still wrong. That space has never been previously announced, it's assigned to APNIC for _research_, it's in dozens of makes and models of router as admin interfaces, blackholed or otherwise.
I get the impulse to say "you used it wrong, now it's broken", but we didn't get to a functioning worldwide internet with that attitude. We got here by observing what people were actually doing and coming to a consensus view on what to break and what to carefully tread around (you know, UX). This is an obvious example of the latter and the fact that APNIC let CF use this space for a production platform in the name of breaking shit is frankly disqualifying (in terms of their overall trustworthiness as curators of essential IN infrastructure).
I don't disagree with you that things have coalesced by consensus over a period of the past 25 years, for what IP space people should and can use, and what IP space you shouldn't use (eg: I have no doubt that a bunch of enterprise end users are using some of the US military/DoD assigned /8s internally, because those never show up on the global internet. It's wrong, but they do it anyways).
However, the RFC1918 IP ranges have existed for a very, very long time, as have the standard documentation/example IP ranges which Cisco, Juniper and others have been using in their training and example publications since 1995 or so. People have had more than twenty years to number their internal networks into the ranges that, also by consensus, the global internet community has decided to make non-globally-routable (192.168, 10.x, 172.16, etc). RFC1918 was published 22 years ago so there is really no excuse.
If you are using 1/8 in the year 2018 for your own internal production traffic, you are wrong and should feel bad. IANA and APNIC (and APNIC's contracted partner, Cloudflare) should be able to begin using ranges as granular as an individual /24 within this /8 on the public Internet without worrying that people who have misconfigured their shit will have a broken experience. It will take time for people to move their misconfigured erroneous configurations into normal RFC1918 IP space, but it will happen eventually. Or maybe not, if v6 adoption speeds up this becomes irrelevant.
I get the impulse to say "you used it wrong, now it's broken", but we didn't get to a functioning worldwide internet with that attitude. We got here by observing what people were actually doing and coming to a consensus view on what to break and what to carefully tread around (you know, UX). This is an obvious example of the latter and the fact that APNIC let CF use this space for a production platform in the name of breaking shit is frankly disqualifying (in terms of their overall trustworthiness as curators of essential IN infrastructure).