This is because we lack Ruby 3 support:
It looks like a week ago fog-google 1.14.0 was released but the ~> 1.11.0 pin doesn’t allow this version.
Bundler always retrieves metadata for all the gems mentioned in gemspec etc, even if the group excludes it. I think the reason is that it allows turning groups on/off easily. That’s also why it always does a git clone even for gems that are in a group that’s disabled.