That's not what you said above. You claimed that the mere fact that it's a hardfork means that you cannot implement anything to only activate if there's a majority. But it's extremely simple to do so. Just check whether a supermajority or a plain majority of recent blocks have signalled support for the hard fork, and only produce hardfork blocks if they have.
Quoting from the blog post https://blog.ethereum.org/2016/07/15/to-fork-or-not-to-fork/
>The community tool carbonvote will be used to set the default fork option for Geth. At block number 1894000 the votes will be tallied, and the outcome will determine whether the default is set to fork or not to fork. Then merging the DAO fork PRs will proceed, followed shortly by a release for both Geth and Mist.
So they're only going to merge the hardfork code if they already have the votes.