Yeah, the OP's argument could also be used to shame people for playing video games.
How much power does a typical gaming rig draw these days?
The logical end step of these trains of thoughts is always the same. If you aren't contributing to the solution in a big way, you should kill yourself. And even if you can't take that step, you should absolutely not have children, and advocate that others do the same.
Viewing energy use as an axiomatic evil necessarily leads to the removal of man from the earth.
No shaming in my argument, only pointing out that the “no harms” claim is bullshit.
Presented like this, the argument is complete bullshit. Anything we do consumes energy, therefore requires energy to be supplied, production of which has negative side effects, period.
Let's just call it a day on civilization and all (starve to death so that the few survivors can) go back to living in caves or up the trees.
The real questions are, a) how much more energy use are LLMs causing, and b) what value this provides. Just taking this directly, without going into the weeds of meta-level topics like the benefits of investment in compute and energy infrastructure, and how this is critical to solving climate problems - just taking this directly, already this becomes a nothing-burger, because LLMs are by far some of the least questionable ways to use energy humanity has.