I don't know about other open-source LLMs but OpenAI is very careful to make sure ChatGPT operates a certain way, according to whatever values reflected by the company itself.
For example, they recently patched GPT4. Before it was able to provide a summary of online articles including those under a pay wall. Now if you tried to ask GPT4 the same question you'll get a response saying that you would have to pay for it (or something like that). Providing a summary of an article under a paywall isn't even illegal (it's like asking for a summary of a book you didn't buy) but in this case it doesn't reflect the view of OpenAI. The model itself didn't appear to be bias, regardless, the code was changed by humans to prevent it from providing specific information in order to conform to OpenAI's personal views.