It is a bit confusing, but I'm not sure that this is actually an error. It sounds like he may be in a position to directly make that change to Chrome, but is trying to clarify that his thoughts on Firefox and Safari are his, and he can't speak on their behalf. When you read it that way, it makes sense.
What's more, Firefox previously adopted a related thing that agl invented (HSTS preloads in general), so he has personal experience of their being amenable to this sort of thing.
The Chrome SSL team works very closely with that of Firefox.
not to mention Firefox pretty much uses the HSTS preload list that Chrome does.