You probably need to follow up with them, noting:
- PageSpeed Insights (PSI) is an analysis tool to make suggestions about how to make your site faster. It is independent of server infrastructure. This mailing list is for discussing PSI.
- PageSpeed Optimization is a server or proxy optimization framework to implement speed improvements, with a C++ library, and predefined server-modules for Apache HTTPD, Nginx, Apache Traffic Server, Microsoft IIS, and Open Lightspeed
It sounds like you are interested in enabling PageSpeed optimization for your Firebase server. However, the Firebase team might have though you just wanted to do analysis, and was confused about the difference between PSI and the optimization modules.
It is possible for Firebase to incorporate PageSpeed Optimization as a feature on their servers, and pull from users may motivate that to occur.
-Josh