I've seen numerous posts noting the sharp decline in contribution soon after the acquisition was announced.
https://news.ycombinator.com/item?id=22601451
https://news.ycombinator.com/item?id=21142934
Without an official explanation, given the timing, it'd be reasonable to assume you pulled development resources away from it, the exact thing you actually went on Reddit to claim you wouldn't do:
https://www.reddit.com/r/AMA/comments/8pc8mf/im_nat_friedman...
P.S. I've observed that these kinds of posts tend to turn into a place where people shit on Atom in favor of _insert preferred other editor here_. Feel free to do that here too, but just note that I'm not going to be obliged to engage since it's completely orthogonal to the topic at hand. I think any remaining Atom users at this point are likely already painfully aware that Atom has long since lost the war in developer mindshare, but don't let that stop you from pouring salt on the wound.