Well, I compared it with Unity build-in Text, seems it behaves the same. (It will put "Looooooo" on the first line if I use ", " instead of ",").
Viewing post in Break text only for alphabetic writing words?
Oh, you're right though, maybe the English "," should be added to the list of linebreak-friendly characters, too? I'm trying to think why i wouldn't have included it on the list in the first place... Feel free to give it a shot, and let me know if you prefer it! Either way, I'mm make sure to push the changes for the next update, so thank you for reporting this!