There's a big difference between NYT/Guardian, which de facto are somewhat independent private media (and not quite aligned with Trump and May), and RT, which is a fully controlled instrument of the state, implementing only state policy.

People in the intelligence community consider Snowden a Russian asset now. Russia could've flipped or co-opted Assange since the Bush years, or maybe it's only now coming out. Either way much of this stuff is classified, so we can't really know details one way or the other. But if you keep up with folks in the IC and look into how Russia does warfare, you see they've been doing this forever, and they're pros at it.