Honestly, I don't think we can be so certain. Both Sweden and Finland made it pretty clear that they would pull out from the tournament last year if Russia played as well. They likely mean it this time too.
In addition to that, the NHL making Prague a host city pretty much confirms that they are aware of such a risk. If they allow Russia in, the Czechs would pull out, forcing the league to search for another location, basically shooting themselves in the foot.
They can choose between inviting Russia and losing three big teams.