Thanks for the vote!
As for whether we entered ourselves into the wrong category, I would be sooo impressed with us if we did and still got nominated.
The category is pretty broad so I understand where the confusion comes from when you compare the nominees.
This is the category write up that they showed from last year where Discord was the winner:
Sites creating and facilitating online community, connectedness, and/or communication around shared interests. These sites can target either a broad-based or niche audience and can include social media sites.