I hand quilt pushing the needle with the fingernail of my index finger and my thumb. I never properly trained myself to use a thimble so I find it awkward. The reason for using the middle finger with a thimble is to allow your thumb and index finger to be thimble free so you can grasp the needle when pulling the needle through and also for starting your new set of stitches. It is a more efficient use of time and energy doing it that way. But I do it the way I am comfortable doing it. It may take me longer but I manage and I have also achieved even close stitches.
If you want a visual to show your family members who say you are doing it "wrong", do a search on the quiltingboard for posts made by borntohandquilt. She does one stitch at a time and has won ribbons at international shows for her hand quilting. She also posted a tutorial here
http://www.quiltingboard.com/tutoria...g-t142087.html on how she quilts, one stitch at a time! Also here is a sample of my hand quilting doing it "wrong" by your family member's definition using my index finger and thumb:
[ATTACH=CONFIG]456662[/ATTACH]