For this post let’s assume the people involved are or were in the past friends, and ghosting is leaving someone on “read” for more than 2 days.

This doesn't match how I'm used to seeing ghosting defined.

That behavior might be unfriendly, but there are a ton of innocuous reasons people do it. People are busy and not every message merits a prompt reply. If someone sends me something that requires more time or attention than I have at that moment like a video or news article, I'm likely to make a mental note to look at it later. I might actually remember, and then remember to send a reply about it. I might not.

It's maybe a little rude not to respond to something more important or time-sensitive, but I can always ask again or use something more synchronous like a voice call. People are busy, life happens, tech can be unreliable. It's best not to assume intentional disrespect.

My understanding of the term "ghosting" is permanent or long-term cessation of communication over all channels without explanation. That should be reserved for situations where someone is a physical danger or behaved in a manner so egregious they almost certainly know what they did.