I don’t really understand this consistent theme I see (on this forum exclusively) that an adult child cutting a parent out of their life is “toxic”—but the age-old “falling out of touch” style is just fine? As previous posters have pointed out, estrangement has always existed. It’s just that now, technology has evolved so that it is much harder to do the “drift apart”. People who don’t respect boundaries or feel they shouldn’t apply to them can use phone, email, texting, etc to continue chasing someone who is trying to leave their life, which is why I think many choose to make the “cut-off” explicit. They may also feel that it’s more fair to be clear about the estrangement than to leave the person estranged wondering where they are, perhaps. Either way, it’s not toxic or abusive to leave a relationship. I am entitled to no one, not my husband nor my children, and I keep that in mind when I choose how I treat them. It is only my children who are entitled to my care and love—because I asked for them, they didn’t ask for me. If they choose to leave me when they grow up, that is their right. We all are free to remove ourselves from a relationship.
Certainly there may be those who end said relationship in a toxic way (I saw blackmail mentioned), but I should think that if they are such a person, you’d be glad to be estranged from them. I certainly wouldn’t want anyone who tried to blackmail me in my life, and I’ve been heartily relieved to get away from them in the past.