Duma is the place where some lawmakers are able to express their opinion. However there is no freedom of speech in Russia, so the opinion cannot be against general agenda. As for constitution CB is fully independent and this guy’s offer have no chance to pass constitution court to become a law. That’s why you see faces like these, because everyone understands that this is populism from one particular person. With 21% rate CB is not popular among any part of society, so publicly poking it will bring political points, it’s the only purpose of these words.
Regrading freezing people’s assets, why CB should be even talking about it when they are able to print whatever amount of roubles they want? The freezing have a point from ministry of finance in case if they ran out of money. However fake-makers not bother themselves to learn how the budget works and give this “freezing” role to CB.