I can confidently state that I am unaffected by text which I see whilst scrolling but do not read. To purport otherwise is nonsensical - if the brain does not deliberately comprehend and then commit observed text to memory, it is not stored and consequently unable to affect the reader. Billboards which you pass on the highway but do not read do not affect you.
For me, as long as a discussion about a topic is logically segmented, whether it is arbitrarily designated as a “topic” or “response” has no effect upon me. Think of a filesystem - it is a simple hierarchy of objects, and yet entirely comprehensible and traversable:
A hierarchical conversation should not differ (except that each comment is more frequently multi-line).
Regardless, that’s a rather unsubstantiated opinion, even considering what supposed evidence that you’ve provided:
The example (if I’m correctly identifying the example as the <details>-encompassed section) which you’ve provided doesn’t appear to demonstrate that. However, I understand what you mean, because it’s quite simple to consider a situation in which a threaded response contextually depends upon what it responds to.
However, why do you state this? I ask because all that it appears to demonstrate is that some threads should not be separated into new topics, irrespective of their relevance to the original topic.
I’ve no idea of what you mean by this. It’s too vague.