The guidelines state "3.1 - Apps or metadata that mentions [sic] the name of any other mobile platform will be rejected."
The poster states the app was approved previously just fine: "SeaNav US has previously been approved by Apple with no problem, we have had Pebble support in SeaNav for nearly 2 years" The poster gives no reason to believe the metadata has changed recently to mention Pebble.
Granted this is based on one example, but it seems unfair to say this was already the policy.
Here's a second example, the official Fitbit app, which does repeatedly mention the Fitbit device in the metadata. https://itunes.apple.com/us/app/fitbit/id462638897?mt=8
Many of them seem to be there as justification to choose from if they see something they don't like.
But regardless of whether it's evenly applied or not, I don't like their policy.
Their description is extremely vague.