Sorry, that was not intentional.
I’d be much more worried about some of the broadcasts from the 1930’s. But I think that “our signals are mere noise” would depend on information about the receiver’s capabilities.
As a side note, I tried to look up recent articles about the narrow-band radio signal from Proxima b. The only fairly current hit I got is the one previously mentioned here on SD about The Copernican Principle. I still don’t understand that with respect to this signal. We aren’t privileged observers of the universe, but there has been life here for a long time. We might not be privileged observers, but we have a privileged location, because there is life here. In other words, the Copernican principle shouldn’t rule out a technosignature from Proxima b, because it might be there because of us.
Pandemics. A small-pox pandemic would pretty much bring civilization to its knees. Or maybe Ebola with a few mutations that make it more slow-burning than it is. A highly virulent H5N1 could do it too.
There’s a big difference between “bringing civilization to its knees” and “wiping out the human race”. Given how poorly society held up during Covid, I’d say it wouldn’t take much (a couple of percentage of the population IMO) to do the former. But that wouldn’t make the human race extinct, it would just be a bad time for all. To actually make the human race extinct you’d need upwards of 99% wiped out I think (99% still leaves 70 million humans, that’s a pretty healthy population for a large mammal) There could theoretically be a single pathogen that could do that, but I don’t think the ones you mention could.