if the blobs were built into firmware, so didn't need to be shipped, would you then say its a 100% open source software device? I'm not sure there's a huge difference.
That seems like a separate question? Like, I'm not strictly opposed to getting into an argument about the line between hardware/firmware/software and if/when/where blobs are tolerable, but in this case it is completely unambiguous that the software Pebble ships includes software that is not open source, while writing a headline that claims they are shipping 100% open source.
their suite is open source, what's needed to run on a particular hardware device isn't fully open source.
example, could one create a "VM" to run a virtual pebble watch without any of the firmware blobs? (I'm not saying that one exists today, just speaking theoretically, ala a virtual android environment).
Does that mean their software isn't open source? I'd argue no.
One could argue that trying to pass off the pebble watch itself as open source is perhaps "wrong" (but as you say, can debate the value of worrying about blobs), but I don't think that means the "pebble watch software" isn't open source as the title says.
Or better put, there's no legal restrictions on someone creating a "pebble competitor" using the pebble watch with different hardware (that doesn't depend on the blobs included for current hardware).