To be clear, Unsplash never provided images: they created a website that accepted user submissions, that's it. All content in Unsplash is user generated.

What bothers me about this sale is exactly this: Unsplash cashed in on their user submissions without guaranteeing their users (and use!) would be protected and perpetuated.

This is equivalent of me building a little lemonade stand, inviting a neighbor that makes a good lemonade but doesn't have a very visible stand to come give away their lemonade on my stand, and then selling the entire stand (with lemonade) to Lemonade Store down the street.