Blogs-mu - Global adminbar takes 3+ seconds to load per page

I just noted that Global adminbar was causing my pages to take 10+ seconds to load - because it was missing and caused a 404 error to invoke. When I found it missing (apparently deleted during some past upgrade), I replaced it with an old version from my backup. I have followed the suggested upgrade schema for the plugin.

Now the file load causes a 3+ seconds to load each page on the entire set of sites on the network. This is a killer for my users and search rank.
I'd really like to disable it!
Found the old "hey comment out this line" - but this no longer seems possible with the current versions.
How can I disable this - preferably without editing the theme which will break all future upgrades?