open source software getting backdoored by nefarious committers is not an indictment on closed source software in any way. this was discovered by a microsoft employee due to its effect on cpu usage and its introduction of faults in valgrind, neither of which required the source to discover.
the only thing this proves is that you should never fully trust any external dependencies.
just a guess, but in order for an LLM to generate or draw anything it needs source material in the form of training data. For copyrighted characters this would mean OpenAI would be willingly feeding their LLM copyrighted images which would likely open them up to legal action.