I'm not sure about this, but I believe US applications go through the Ottawa VO. Given that there are very very few US applications compared to other VOs, it makes sense that the apps are processed faster.
That being said, I absolutely do not buy into this idea that US applications are processed faster. There is zero data to suggest this. There are always straightforward applications which get processed quickly, and this person had prior biometrics too. Fewer interruptions in processing.
If you look at immitracker, April apps are more than 80% complete (so they met the service standard). May apps are close to 50%, and June onwards see a sharp drop off. with only 1-5% apps in following months being processed. None of this is out of the ordinary, it does not signify faster processing (with respect to the service standard). Immitracker is certainly not a representative sample of the total immigration set, but it's the best we have. Focus on the stats and numbers, not on the individual anomalies.