I actually think it's all largely flawed but it's possible the changes did that. I did find it interesting but the sample size is small. I will note that the OP article ignored the left to far left pipeline and showed a clear bias and many of these people claiming as much mislabeled a lot of normal content that was libertarian alt right and what not. But yeah it's after. Good point. Not sure if you can say the changes worked for sure. I'd like to see a more comprehensive study over time from before and after.
No, you are completely right about that. I think the study is correct in that youtube just makes people more partisan and I think the internet, reddit, twitter, facebook, the internet as a whole makes people more partisan, left and right. I agree with that completely. These sites just let people stay in their own echo chambers. Its why I actually enjoy this forum because I DO hear other perspectives and this little forum part of a much larger community is one place that isn't an echo chamber even though there is a lot of poo flinging around here.