Is this ever appropriate to say to anyone, especially a stepchild?

Here's a lovely transcript of the voicemail I received last week. (Click on DivShare link at the bottom.)

More stories to come. I suppose I'll start with the most recent and work my way backwards. Here's the transcript from my stepmother. Necessary backstory: My parents divorced in the 1990s; my father left my mom and married his former secretary.  She's now my stepmother.  At the time I got this, I actually had no idea what she was talking about or what prompted the message. More on that in a moment....


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"It's about 10:30 on Tuesday morning and I just wanted to let you know that as far as I'm concerned, with the other information that I've recently found out, you're not welcome up here.  You are not welcome to come up for Thanksgiving. You're not welcome to come onto our property or into this house if you want to see your father. He can meet you outside once is up and available. And just to let you know, I have been having a sexual affair with your father since 1975 and he had affairs with other women during your mother's marriage to him. Okay, so here now we have everything on the table and just to let you know, he even slept with somebody before the night before he married your mother too. Okay, so if you wanted to tell your
mother that too, so this way, everything's set out in the open. Okay. Take care.
**


Now, the truth is, I did nothing to warrant this. Truly. Nothing.  The stepmother is actually psychotic. She thinks (I found out later from my father) that I called social services and reported her unfit to care for my (recently out of the hospital) father. This isn't true. I didn't call anyone.  All I did was talk to her (stepmother) and my dad during the week he was in the hospital. That's it.  It doesn't take an actual, real, logical event to set off psychotic people.  More craziness will follow. Just wanted to share the beautiful gem above for starters. The follow-up to this is that I wrote my Dad and let him know what she said. How he responded is just unbelievable. But that will come another time. Sit with this for a bit.