>>In other words: these employees would have lost their job regardless of their union status

IDK that we can make that assumption. Instacart management has made themselves out to be anti-unionization (a common view by management in the US). If you're an anti-union manager, and you're about to make a massive, 2,000 person layoff declaration, you're going to make sure the unionized group of 10 people is on that list. Can't let that sort of thought spread to other locations, and this serves as a good example to those trying to organize in the future. It's easy to avoid a NLRB loss if you bust the union as part of a larger layoff.

The only thing that would have been telling is if they had announced a huge layoff and NOT taken out the union shop.