Insecure (you get everyone's IP addresses, if you find a vulnerability you may be able to execute code on user's computers instead of just a server)

Prone to significant lag (one person's bad internet can affect everyone).

I'm sure there's quite a bit more reasons that I can't think of now though

Also intention is pretty important when determining the guilt of many crimes. OpenAI doesnt intentionally spit back an author's exact words, their intention is to summarize and create unique content.