It's so mind-boggling that they have control over the default browser home page and the news feed on everyone's taskbar and they choose to show gossip and one weird trick that doctors hate. Don't they feel embarrassed that they pollute their brand like this? Is the revenue from the clicks really worth it, or do they just not care?

While crazy to us, I bet we're in the minority. Average computer user might actually like it or at worse (to MSFT) not even notice it. Their web experience is bombarded with "1 weird trick" ads everywhere.

I don't think it's about revenue from clicks; they probably believe that it is what customers want, because those customers click on it. That surely means that they want it.