That bit is easier for me than for you, perhaps, since gmail implements about four RFCs I've written ;)
That bit isn't the MSB, though. The MSB is that they do care about fixing interop problems with everyone, they just don't read mail from randoms. I think they assume is that if a problem is their fault it will show up on their monitoring graphs, and watch their error graphs instead of their postmaster inbox.
How did you even get your report to be read by an engineer at Google? This seems impossible unless you have some kind of business connection.