Yup. The sad truth is there’s no shortage of videos out there just waiting for you to engage, they will feed you literally anything at all as long as it gives them a click and some advertising money. It’s the scariest part about social media and the algorithms, because many many people are not even conscious enough to question what they’re being fed, and will just mindlessly soak it all up and take it as fact.
On the one hand yea it’s out of control and is partially to blame for the dumbing down of society, on the other hand it’s just the evolution of tabloids. People have always been bored and gullible.
People who watch conspiracy videos tend to watch a lot of conspiracy videos, which the algorithm likes. So if your watch history suggests you might watch a conspiracy video, it'll suggest them to you so that you'll hopefully get pulled in and watch a bunch of videos.
To add to the other reply, you also don't need to watch a full video, they register slight pauses as you scroll. They also build a profile using all their platforms and multiple types of data.