To answer the original question you have to look at it from a historical stand point and from a historical point of view the catholic church came before any other protestant denomination which were developed over 1500 years after the life of christ while the catholic church is much much older and i will give credit where its due the first five books are the Jewish Torah written by them

Catholics do not worship Mary they honor her as a great and holy person as far as prayer goes prayer means "talk to" that is why it is alright to pray to deceased loved ones saints Mary and most important Jesus however in the RCC their are 4 types of prayer petition, contrition, thanksgiving, and adoration. the first three can be to any of those mentioned above but since we only adore God( not Mary or anything else as you may think) we can only pray prayers of adoration to Jesus(God) i hope that explains it