@Aaron H Who has any reason for a TabStop on a label? If you need it, turn it on. It should not be on by default.
Some accessibility users, particularly vision impaired or blind people. For them, enabling an OS setting to have the system read the labels as they tab through controls can be helpful. Or even the only way they can use the computer at all.
But note that to be helpful you MUST also properly set your "tab order" so that the label immediately precedes the associated text field. And your tab order of fields should be logical too.
Having a logical tab order is helpful for keyboard centric users even with good vision, but for visually impaired if your labels are not properly sequenced to associated fields you will make life very difficult for those users. And to a lesser extent having the tab sequence jump all over the screen can make usage harder even when the labels' tab order precedes the data.
Try navigating your program with your eyes closed and using the tab key and see what happens...