This is correct. This is exactly why I am taking the regional to connect at New Rochelle, rather that taking the Acela to connect in Stamford (and backtrack via MetroNorth).
For the past 30 days, Acela 2150 arrived in Stamford with an average delay of 15-20 minutes (which would have caused me to miss the MetroNorth connection). In contrast, Regional 190, operating just a few minutes ahead of the Acela, arrived in New Rochelle on time every day.
I still think it is bad public policy to prioritize one government agency over another.