All because you said no to going to church? My opinion is, Dad and Step Mom need to get a clue. You have your own life and you make your own decisions.
After work and being at work the day before a holiday is generally a nightmare anyway, of course depending on what you do, you want to get home and just relax a bit. Not shower, get dressed up to go to church.
Tell step mom to get over it, it's not the worst thing that has or ever will happen in her life.
My mom lives about 3 miles from me and my sisters live 1000 miles away. I'll take mom over the sisters anyday. I have one that keeps asking me to drive up to her house when I'm on vacation to work on her house for her. She'll feed me and give me a bed.
Sure sis, who's going to pay for my fuel up and back at 12mpg? And I work at my contractors rate of $30/hr and all you want to do is feed me? Not me baby.