It's not so much that people end up with a lot more food than they need and throw it out. It's the wastage at the supermarket and elsewhere in the distribution chain. Furthermore, I suspect the meal kit companies are tending to replace takeout of various sorts and eating out more than they're replacing conventional shopping and cooking.

And there's lots of waste throughout in those cases even when it's not visible.

It's hard to quantify any of that but, plastic bags or not, I suspect Blue Apron is relatively environmentally friendly.