FarNorth I agree completely. I'm not saying the OP is doing This, but it's very common that overbearing people don't see everything they're doing, or else actively try to deny things they have done.
All I hear from the OP is a lot of how unfaaaair it is that she's been cut off and how all she wanted was to see her graaaandbabies and how they essentially wouldn't let her walk all over them and as a consequence they need to get back in line and she's pressuring them to do so.
Sadly it is quite possible that a lot of this may have been in place before DS and DIL got together. It's just that in some families (again not necessarily the OP's) there is a rule of "don't rock the boat because Mom will throw a strop". It's easier just to go along to get along. But when someone new comes in and recognizes that the dynamic is unhealthy, that person is often able to bring people around to recognize how unhealthy the situation is. This brings people out of the FOG and upsets the applecart - and Mom throws a strop because she's not in control anymore.
Govt announces Ukrainian style scheme to bring thousands more migrants to UK
What is the most random school memory you have?


happens to us all.