It's incredibly frustrating how people fail to really understand how this list works. Every. Year.
It's not about who's doing what at the NHL level. It's what they think his top potential is.
The "rankers" believe Gardiner's potential at this point is a tad higher than McDonagh, not because Gardiner is better than McDonagh right now but he probably will be in the (near) future.
You can surely disagree with the ranking if you believe that McDonagh has a better ceiling but seems like the only argument I've seen from the angry Rangers fans is that because McDonagh is at the NHL level, it makes him a better prospect automatically.
mcdonagh has an elite combination of size and skating at the nhl level. combine that with an already good understanding of the defenseman position and hes a great prospect. this is only reinforced by getting top 4 minutes in the NHL and being a +17 or so in like 40 games.