Astral_AbyssMassdrop is more than just a group buy website.
" Massdrop creates high-quality, custom gear, apparel, and products inspired and designed by our online communities. We provide millions of members a place to connect, discuss, buy products together, and learn about the things that are important to them."
Source: https://www.massdrop.com/about
You've been on Massdrop since 2015, you should know this by now. Massdrop does many collaboration projects taking ideas from the community and creating new products. This is the first run of one of those, and there have been many instances like that on massdrop that you would have seen.
Edit: It also is a group buy because massdrop isn't the manufacturer/retailer, we all give our money to massdrop, they give it to the manufacturer. The manufacturer sends the keyboards to massdrop, massdrop distributes it. Still a group buy.
Edit 2: Also, kickstarter: https://www.kickstarter.com/projects/massdrop/massdrop-x-input-club-k-type-mechanical-keyboard