How do you sew a curved hem? Sewing Machines Parts and Sales in Los Angeles

I’ve been following the steps of the following tutorial for hemming mens dress shirts however I am left bewildered when I finally try to fold and stitch the hem. This step occurs at about 7:56 in the video. I’m able to fold and stitch the hem in the beginning however once I get to the curved bits, rather than folding nice curved hem lines I get these weird angled hem lines. How is it that the lady in the video is able to fold a curved hem whereas I keep getting sharp angles?

I should note I skipped the step at 6:18 because I felt it was an unnecessary step, I didn’t see the point of it?