'tis how LLM chatbots work. LLMs by design are autocomplete on steroids, so they can predict what the next word should be in a sequence. If you give it something like:
Here is a conversation between the user and a chatbot. <insert description of chatbot>
<insert chat history here>
User: <insert user message here>
Chatbot:
Then it'll fill in a sentence to best fit that prompt, much like a creative writing exercise