I think a psychologist would say that if you really can't find common ground, it's best to agree not to talk about it.
Indoctrination is highly effective. Your parents were raised in a place where toeing the line is the norm and questioning those in power is traditionally a great way to ensure you disappear. Russians are deeply indoctrinated when compared to western nations because that's how their society has been set up since 1922. The Soviet leadership ruled by suppressing any dissent, violently and without remorse.
Just because the Soviet Union no longer exists, doesn't mean their ways of doing things disappeared too.
The only way to change them would be to engage in an equally sophisticated program of indoctrination: deprogramming as it's called. Since you lack the resources of the Soviet Union, it would be a much more difficult task, especially since your parents are now older and their brains are less changeable. They were indoctrinated as children and by a very prolific system. Reversing that now, by yourself, is a tall order.
I'm sorry your parents were failed by their leadership, it's truly a shame.
Of course the URL has to appeal to the wannabe driving his lifted pickup truck, it has the word warrior in it. You get all these meatheads with delusions of being some sort of Spartan badass because they took 300 as a documentary.
They supported him, what the hell did they think was going to happen?
There's a reason we don't let rabid dogs roam wild. If you open the cage, you don't get to complain about the subsequent rabies epidemic. You certainly don't get to ask the dog to stop biting people.
Agreements of any kind are pointless when one party will simply ignore them. It would be like signing an agreement with a rabid dog, and then getting pissed off when it bites you. Telling him "You didn't abide by the terms!" isn't going to make the slightest difference.
If you goof around near the edge of a cliff, don't be upset when you fall off.