There's a lot of people who don't fact check anything for themselves, even when it comes to something as important as voting for a leader of their own country.

You're right that the disinformation about chemotherapy could kill a lot of people. I'm usually against laws regarding the right to speak, but there should be some sort of consequence for spreading blatant misinformation about important matters such as health and politics.

In the past when there was no internet media, the newspapers could be held acocuntable by some Government body. However, they abused that power and they merely became propaganda tools. The internet allows us access to vast swathes of information and opinions which is a blessing. It's up to the reader to be more diligent though and stop accepting information at face value.