I listened to this episode on my morning commute and was surprised to hear Chris and David mention a couple of my WordPress plugins, most notably Nomention.
David better explains in the podcast why it was decided not to include my request for such functionality in the plugin: rather than just a feature it was adding a new property to webmentions which needed more community discussion, and it was felt that my suggestion of a nomention class may not have been the best way to implement it.
I completely respect that and agree that a discussion should be had to determine if there is a wider need and any possible solution. What works for me and within WordPress may not be a valid option for other CMSes or even for the spec itself.
As I wrote when I created it, this was designed to fill an individual need and fit my specific workflow and, as David also mentions, if something doesn't exist then it's the indieweb way to create it yourself.
The original suggestion that a nomention was essentially
rel=nofollow didn't fit my circumstances (adding a class to a link using MultiMarkdown) but Chris mentioned in the podcast that it also has its own issues: by default WordPress adds nofollow links to comments which could impact threaded conversations via webmention.
I look forward to any such discussion when or if the community deems it appropriate.