And at least in the US if you're a hobbyist at home then there's ~no regulation whatsoever beyond the requirement to permanently affix a serial number and to keep accurate records.
I don’t think anyone is talking about homegrown LLMs, this is commercial products for sale.
I don't see the difference when it comes to the ethics of making a tool available to the world or teaching someone something. Like who cares if it was a hobbyist versus a professional tutoring outfit that taught someone expressing an open interest in committing terrorism about the chemistry of explosives? The two hypothetical teachers are equally at fault as far as I'm concerned.