Is Ice-Q even part of CHEL?

Unfortunately, the video does not show how the other team gained possession, which was likely a turnover. This is crucial in determining the main factors that lead to your opponent being able to generate so much speed. 

Based on the fact that all human forwards are shown to begin transitioning to the backcheck at the opening of the video, we can only assume the puck was turned over right before the video begins. 

The turnover (which was likely at the hash marks against the boards) puts the RD in a flat-footed position. This is why turnovers are so costly. You'll have some players in worse positions than others, preventing them from being effective.

In this case, the RD was hamstrung by a turnover. He takes a moment to react (which is 100% realistic) and then begins back skating. The opponent times the pass right when the Ai-D begins their transition to back skating, so there's no interception. 

During this quick succession of events, #47 (the eventual recipient of the pass) is able to generate a ton of speed, unimpeded in any way. because the turnover has thrown everyone out of position. 

Now, the CPU D-men should have the capacity to match hustle with the player they should be covering even when they don't have the puck. This clip is good because it shows how the CPU D will not hustle until their checked player actually has the puck. (watch how the CPU D has two hands on his stick and instantly transitions to one hand on the stick the exact frame the pass is completed)

This explains why they can never seem to catch up to a player that's already been hustling before they get the puck. The CPU D then has to try and 'catch up' with a puck carrier that may or may not have a higher SPD attribute (ACC is irrelevant by this time) than them. 

The other frustrating thing is that the CPU is will within the range to execute a stick lift or a DSS-poke check on a few occasions and they just passively let the shooter have their way:

At the end of the day, there were human errors that led to this opportunity but I will say that the CPU needs to be a little more aggressive when getting in such close proximity to a puck carrier and they also need the ability to match hustle against a player who is hustling without the puck.