I 2nd that... I handle mine all the time as well. Ive never had any issues with injuries nor stress. Actually if you want honesty, my favorite female griffin mantis enjoys coming out and will come running at me when she catches a glimpse of my hand. Same with many of my past favorites, the more interaction your mantid(s) get with you the less it sees you as a threat.
Same with many wild life forms, you show it love and affection. Less of a threat you become.
My girlfriend has a pet squirrel (yes, a wild squirrel.) she's had now for 10 years.
Ive got a test: If you can find a location of natives in your area. Go out and collect 2 specimens. House them separately but give one daily attention for 1 week (taking it out, interacting, offer honey, roam house plants.) while only giving the other its necessities (food,water,enough room.) and see which is more likely to come out to the sight of your hand at the end of the week, rather than flee for its life like in the wild.