Could argue about categorising all illustrations as same because a Twitter feed said so. As a designer, I'm pretty sure you wouldn't want your own work to be dismissed like that, without much thought by anyone with an HN/Twitter/Reddit account. But won't argue on that too.

What I think is really unfair to mention is that unDraw has contributed to the commoditization of illustrations. On the contrary, there have been many many projects available to illustrators just because the initial design/proposal/prototype could be built with that and win over the clients. Project designs that would otherwise use photographs but not illustrations.

Sites like Upwork, Freelancer, etc. existed long before unDraw and you could find creative work there for truly humiliating prices. It's extremely inaccurate to blame unDraw for that.

The fact is that unDraw helped bring attention to illustrators and illustrations, which were called icons even a few years ago, by opening up a discussion and many new projects.