Why is it any more interesting than any of the other thousands of people that dislike the idea of hiding dislikes?
If that opinion was so important that caused the co-founder to launch a campaign to wrestle control back, then let's get the popcorn. Now we have something interesting and that former co-founder's opinion suddenly has meaning. Otherwise, they really don't care and are just mouthing their opinons to see their like counts go up (but not their dislikes because, phew, those are hidden now)
Many HN readers think the visionaries who actually create billion dollar businesses have more valuable opinions/insights than the visionless corporate bureaucrats who ultimately end up in charge.
Because it's from the co-founder of YouTube? Surely that gives their opinion more weight and notability than the Average Joe/Jane online?
What is this co-founder's current position at YT? "When the site was introduced in February 2005, Karim agreed not to be an employee and simply be an informal adviser, and that he was focusing on his studies."--wikipedia So, not very influential.
Again, it's just another person's opinion.
* Also from wiki: "In November of 2021, Jawed updated the description of "Me at the zoo" to "When every YouTuber agrees that removing dislikes is a stupid idea, it probably is. Try again, YouTube ".
People build up this mystique around founders/co-founders that borders on religious. I don't drink that kool-aid. I've been in/around too many cults in my life to fall into that trap.
I think you've answered your own question "why is it any more interesting" in this (HN) context.