I have to disagree with the decision to shut down TM-AC1900 discussions. I have owned Asus routers from N66 to 3 AC68u to 3 RT-AC3100 and also an AC88U. I had sold my AC68u to upgrade to AC3100/88U before AiMesh came out. As I was sure AiMesh wasn't mature and I didn't want to spend a lot of money beta-testing for Asus, I got the TM-AC1900 to test before moving my AC3100 to AiMesh with the intent of selling the TM routers after I'm satisfied with AiMesh performance. Now, my beta-testing of AiMesh is more perilous than before unless I want to use my genuine Asus units. There are a number of TM-AC1900 owners who got locked into TM firmware after the lockdown and would like to now use a non-TM and non-Asus forked firmware such as DD-WRT but who now can't. Keeping the discussions alive may have helped them in revert out of TM firmware.
Now, I support Asus in general as a company (bought their motherboards too) and also RMerlin, but if TM-AC1900 is supposed to be a TM product, then neither Asus nor RMerlin should have any say in terms of whether TM-AC1900 should be allowed to be hacked. They can say that you're not allowed to put their firmwares on TM-AC1900 and have every right to booby trap their firmwares to not let you put it on, but it's up to the end-user what they want to do with their TM-AC1900, including hacking and loading third-party firmwares. TM has the right to say that discussions on hacking TM-AC1900 should not be allowed but I doubt TM cares as discussions on TM-AC1900 hacking has been going on for years and TM-AC1900 is a discontinued product (not to mention that TM probably cares much more about running the cell business then its deprecated routers). Now, it would have been nice had Asus let people know about the lockdown before it happened out of good will (though I agree that Asus has no obligation to) and I hope that RMerlin will do that in the future if RMerlin firmwares will also propagate the lock down (though from what I've read, I doubt that RMerlin will take that step).
Above thoughts aside, perhaps the latest hacks to bypass the lockdown scared Asus in that there is no other way for Asus to lockdown TM-AC1900 and that is why discussions on TM-AC1900 have been banned? If that's the case it is unfortunate because well, censorship doesn't work on the Internet (unless you're China) and methods of defeating the lockdown are already out in the wild and will continue to be out in the wild.
Last thought, I hope this post doesn't get deleted as it does not discuss in any way how to defeat the lockdown.