Since Phase One has made it quite clear that they do not intend to support other non P1 MF cameras, it's clear that they don't want the subject matter to be covered on their forum. They pay for the forum so I would say it's up to them what they allow.
You have published this exif hack on LuLa and Getdpi, which allow probably more access to Hasselblad users than the P1 forum, as I would not expect to many Hasselblad users to frequent the P1 forum.
The news of editing the exif header is not new news either, I have done it for years on various cameras that shared sensors. Mostly when P1 was slow to get the support added to C1. As at least 3 other brands now use this 50MP sensor, odds are that you will be able to continue to work like this. However in the long run, at least to me, it's more pain than it's worth. Editing a few exif headers is not a big deal, but editing a days worth, a bit more tasking. I have a great editor with a gui interface, but in gui mode it's one image at a time. You have to run a batch job to make a large number of changes. And you also have to keep 2 sets of files as if you want to use same raw in a non C1 raw converter you would want the software to see the correct camera info.
The dng support issue in C1 is also long in the tooth, odd are it will never happen fully. But even if it did, you are still compromised since you would not have a dedicated camera profile for your camera. I also have supported C1 since early 2004 and would rather that they become a true software solution across the board, but that is not their corporate direction. P1 continues to keep their prices in the stratosphere, however so odds are in time they will either be forced to change said policy or find another direction. The cost differential of close to 12K to 15K will be harder to justify. Also P1 doesn't even have a camera platform to compete with the new mirrorless MF offerings from Hasselblad, Fuji and maybe soon Sony themselves.
But P1 IMO is not being rude to pull the post, they own the site and are just holding the line of current P1 corporate policy.