There is no debate that Demidov possesses 1st overall pick talent.
Pretty much every scout says so.
Also teams don't choose players just based off talent. There's a lot more that go into it such as position, team needs, risks (russia), etc.
Potential top pairing RD are extremely valuable and hard to acquire, and the Hawks decided to go with that.
There are a lot of great centers expected to be there at the top of next draft. So making that trade for Lindstrom doesn't make much sense for the hawks. Demidov makes a lot more sense because chances are there won't be a player as talented as him when the hawks pick next year.