not necessarily, and not when the MOH is a 19 yo unemployed college student who cannot drive aka xsbaby. if you have a sister, she is likely going to be the MOH, regardless of age. xsbaby is not the best suited to organize this, but she is making her opinion heard to the group about what she thinks her sister would want, which is for everyone to get along and not so much THE BEST SHOWER ever. If you are having all friends as bridesmaids, i guess maybe you would pick the one best suited to organizing things as the MOH and hope that she would do a nice job of it. I think Megan and Colleen are perfectly competent to host this, but their interpersonal skills leave a lot to be desired.
My best friend was my Matron of Honor and I was her maid of honor. I didn’t throw a single gift grab for her. Her mother’s friends did that. We were still in college at the time. My sister was a bridesmaid and my mother was ticked about it but it was my wedding, not hers.