My mother was a teacher in Ontario. She insisted her salary should be looked at over a 12 month period, not ~9.5 month. Even though for those ~2.5 months, she was free to do whatever she wanted, including taking on additional full time work (though, more often than not, she vacationed).

No, but this is my free time and how I use it. If I chose to do that during my vacations, no one would be "well poor you, you don't really have 4 weeks of vacation a year, since you decided to pursue professional development during these weeks". People would simply say that I chose to use my free time to do these things, and some of these things are quite essential to my continued employment.

The line between that decision being made freely vs. being forced by labor market competition or other economic reasons is pretty fuzzy.