Firstly, we do not have worthy alternatives (PeerTube and Odyssee are not yet sufficiently developed).
Secondly, I watch them through LibreTube, so Google does not know information about me.
Thirdly, the world consists of compromises. This is one of them.
I think there are defendable grounds for saying someone posting about privacy on YouTube is and is not ironic. How surprising or unexpected it is depends on many factors like the poster's goals, threat models, and degree of altruism, user expectations regarding the poster, and congruence or incongruence with all of the above.
The modern world consists of irony, albeit often sad. The goal of many of them is to reach ordinary people. And they watch videos on YouTube. The end justifies the means, I believe.
This only makes sense if you think Google is the one who puts up all videos on YouTube, and it's not a platform where basically anyone can put up a video about anything.