Why is it "wade through" if there are 10 clearly distinct but dependent commits, but comfortable if it's 10 stacked PRs instead? They are basically the same thing, presented ever so slightly differently.

I think in most teams I've worked with, the majority of developers (> 85%) barely undestand what Git is doing or what things mean inside GitHub, have never seen commit history as a graph, have never run something like "git log --oneline --graph --decorate" or "--format", and have never heard of "git range-diff" which is very useful for following commit/PR/unit changes.

Personally I review using "git" itself, so I see the graph structure either way, and there's little difference between stacked PRs, commit chains in a single PR, or even feature branches, from that point of view. Even force-push branch updatea aren't difficult to review, because of the reflog and "git range-diff". The differences are mainly in what kinds of behaviour the web-based tooling promotes in the rest of the team, which does matter, and depends on the team.

I agree with you if you're using Graphite instead of GitHub. Having a place to give feedback and/or approval on the individual "units" (commits in a PR, or PRs in a stack) is useful, grouping dependent but distinct changes is useful, and diff'd commit evolution within each unit PR in response to back-end-forth review feedback is useful in some collaborative settings. Though, if you know "git range-diff" and reflog, that shows diff'd commit evolution quite well.

In GitHub, people are confused by stacked PRs both conceptually and due to the GitHub UX around them. Most times when I've posted a stacked PR to a GitHub project, other people didn't realise it was stacked, and occasinally someone else has merged the tip of a stack made by me, and been surprised to see all the dependent PRs merged automatically as a side effect. Usually before they get to reviewing those other PRs :-)

People understand commit sequences in a PR, though I've rarely seen people treat the individual commits as units for review when using GitHub, unfortunately. In the Linux kernel world where Git was born, the PR flow is completely different from GitHub: Their system tends to result in feedback on individual commits. It also encourages better quality feedback, with less nitpicking, and better quality commits.