I catch reruns from time to time, but am not a regular viewer.
I personally have struggled with setting boundaries and maintaining them. My 28 yr old son is the addict in my life.
I do not feel the people are issuing ultimatums, I feel they are stating fact that either the addict in their life seeks recovery or there is no way they can continue to maintain a relationship with them. The family members seem to have struggled with enabling and may have reached their bottom and realize that it's time to stop enabling and let the addict deal with their own life.
That is a difficult thing to do, I know that it my struggle. My son is currently seeking recovery on his own so I hope that during this time I can grow and find the strength to take care of myself going forward and let him take care of himself from now on.