I think most, if not all, or at least a significant portion of the people who are interested in a peer-to-peer Reddit alternative also prefer to use open source software. At least link to the github page at the bottom of https://getaether.net/opensource/.
The issue with this is that I got people complaining both ways — the definition of open source isn’t super clear and lots of people have much different understanding of what it means without realising. So the website used to say it, but then people would complain and ask me to remove it. So I removed, now I’m getting people asking me to add it.
Ultimately, yes, Aether’s source is available under a licence that is commonly known to be an open source license by most of the community and the Free Software Foundation. However that was not enough for some people, so instead of dealing with that bullying I just removed it. People who are interested in it (like you) can find it easily on Github, since the Github link is widely and publicly available otherwise in many discussions about Aether online, on Hacker News and so on.