Social media(Videos) doesn't use only LIKE as a factor on whether the content gets more push.
It's likes+watch time. If your grandma spend hours watching the same type of content and at least watched each video in its entirety, then more of that content and from that author will be recommended. Also, Social Media use those parameters to gauge whether to spread that content around or not. The more watchtime, the more the content gets out.
If several people watch less than 50% of a video, video-based social media understand that the specific video is not interesting, thus cutting its reach.
The thing is, some social media like X have specific people they mark for deboosting(cutting reach), not caring on whether people like the content or not. This deboost is normal in most centralized social media, and even in some decentralized like Bluesky and Mastodon.
Bluesky has been known for having specific advisors to tell whether the moderation should deboost someone.