Because users were able to connect and after the firmware update they are not? And also because they didn't even let you change this setting to begin with.
There is not enough data to attribute this to malice yet, but it does not look good (see CloudFlare's tweet).
And they singled out this one instead of Google’s, which has been around since well before NN existed and is far more well-known, because...? I remember seeing talk about this on dslreports a couple weeks ago, IIRC it’s not a deliberate block, they were using this IP or a range internally.
There is not enough data to attribute this to malice yet, but it does not look good (see CloudFlare's tweet).