When you get good sounding information that is wrong, it can be extremely problematic and often much worse than no info at all.

A partially good answer is better than no information at all

Imagine LLMs aiding people with health improvements, only to lead them into health decline (actually already happening, a lot)

Already happening where? How can AI lead you to health decline? It cannot prescribe you medicines or do surgery on you

not to mention the LLMs that further convince people of their conspiracies.

It can also help people understanding if conspiracies are true or false, for example had you ask an LLM about this post it would have highlight to you that there's a good chance that it is propaganda.