When the ribbon is minimized, the File tab appears to be the default tab, instead of the Home or Messages tab.
The solution: don’t minimize the ribbon.
Actually, the File tab isn’t really made default, it just seems so because of the tab color. While it is an extra click to show the commands on the Home tab, its not because the File tab has focus, its because the ribbon needs to be expanded.
If you want to keep the ribbon minimized and reduce clicks, add your most used commands to the QAT or learn the keyboard shortcuts.