I watched the replay on the Remington site - WED 10-16-2019 R6.
Here's what I see:
At first glance, the pan shot makes it look like the #7 cleared the #2.
But a closer look at the pan shot shows the #1 horse on the rail partially blocking out the view of both the rear half of the #7 horse and the front half of the #2 horse. This makes it really hard (for me) to use the pan shot to judge the actual distance between the rear legs of the #7 horse and the front legs of the #2 horse.
That's what I think the stewards are focusing on.
Any time the rear legs of one horse and the front legs of another horse are close enough that a front leg of a trailing horse can make contact with the rear leg of a horse in front - a dangerous situation is created. It's called 'clipping heels' and it's one of the ways a horse can fall while running at speed.
After watching the replay of the pan shot I watched the head on replay (which starts at about the 4:00 mark in the replay video on the Remington site.)
The rider of the #7 horse angles over toward the the rail.
As the #7 horse crosses in front of the #2 horse:
The rider of the #2 horse angles over (Imo, to avoid clipping heels) and in so doing bumps with the #1 horse whose rear end actually makes contact with the rail.
After watching the replay (both the pan shot and the head on shot) I can't really judge whether or not the #7 horse was clear of the #2 horse.
But the head on replay clearly shows the #7 crossing over at a fairly sharp angle, and the head on replay clearly shows a chain reaction behind the #7.
In this particular case, because I can't actually see from the pan shot how much distance actually exists between the rear legs of the #7 horse and the front legs of the #2 horse:
I have to trust the judgement of the stewards and hope they got the call right.
By the way, the DQ in this race makes a good example of the difference in rules used for DQ's here in the US and Canada vs. the rules used for DQ's in other parts of the world like Europe, Australia, Japan, and Hong Kong.
Here in the US and Canada under Category 2 rules: When the stewards decide a foul was committed there is no choice. They have to take the horse down.
In other parts of the world under
Category 1 rules, the stewards decide not only whether or not a foul was committed but also decide on the severity of the foul.
In my opinion, had this same race with the exact same incident been run in Australia, the UK, Japan, or Hong Kong where Category 1 Rules are in use:
I think it highly likely the stewards would have ruled to let the result stand for wagering purposes.
-jp
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caused the 
into the 
, who almost went through the rail.
