I strongly agree. ChatGPT ultimately tries to give you what you ask for - so if certain prompts cause it to give "leftist" (by whatever definition) answers, then one might reasonably conclude that something about those prompts makes ChatGPT think you wanted a leftist answer. But that's wildly different from claiming that ChatGPT itself has a leftist bias - which is a bit absurd considering that it will happily give out virulently anti-leftist answers, if that's what it thinks you asked for.