"We're talking about thousands of people losing their jobs. These people then go into a smaller labour market where they compete with other vulnerable retail workers, affecting far more people."
Expand your time horizon a bit. Having freed up the malinvested resources, other enterprises will arise which will hire them, at jobs that are now almost by definition more solid than the one they left behind, since the one they left behind couldn't sustain itself.
"But what if they can't wait around?" They don't necessarily have to. The job market is not so tight that one job has to instantly open up as soon as one person is fired. There is some fluidity in it. The only place there will be any particular trouble would be around the HQ of Toys R Us; the individual stores are going to be in economies where the store going out of business is just a tiny blip hardly affecting the local retail employment environment.
"But what about the permanently unemployed?" Well, if you're used to the "new normal", be sure to have a look at the current unemployment trends before getting too far into that sort of argument.
And you have to consider the flip side as well. What if you got to go to work for Toys R Us, and it was guaranteed that you would be employed indefinitely there no matter how badly things went for Toys R Us? Sweet deal, right? Well, sure, but it's not going to be unique to Toys R Us, right? It's going to be the deal for everybody. We've got experience with what that "sweet deal" produces; read about the Soviet Union's economy. Would you rather have to find a new job every so often and live in the US, or be stuck in the Soviet Union? We don't have to hypothesize the answer to that; people are still falling over themselves to get into the US.
It is vital that people understand that creative destruction trades some short-term inconvenience for massive long term wins, lest we foolishly legislate short-term conveniences for massive long-term losses because we collectively stopped understanding the full story.