When I pray for someone, I pray directly to God for his grace over that someone. God doesn’t inform me that I must go through Peter, Mary etc.... for him to hear my prayer’s. To insist otherwise is looney tunes.
Nobody is insisting that you ask Mary or anyone else to pray for you. But if I choose to ask Mary or another friend to pray for me, it is my choice. There are many threads on FR asking friends for prayers.