I would be concerned about having what other people post and upload on my server. Even if people I know or allow, storing others people’s data on a server in my home seems dangerous. 

 Why do you think it's dangerous? 

Its just text messages. and you don't owe anyone anything. 

 Yeah I suppose images and videos are hosted elsewhere. I just don't want to be responsible for what other people say. I think if it's on your server technically you own it. 

 Yeah, relays host text only. media files are a whole different game.