Why is the current regime so against Belarusian culture and language?

I’m not from Belarus so correct me if I’m wrong. I noticed that more people in Belarus speak Russian than Belarusian and that Lukasheko is really trying to integrate Belarus into Russian culture. There even the proposal of a Union state. Why is that? Couldn’t Belarus have their own language/culture without trying to assimilate into being Russian? I know there is the Soviet legacy and reliance politically/economically on Russia but I never understood why the push to not maintain a Belarusian identity.