This isn't about "understanding the issue at hand," this is about UX development.
Linux is, very intentionally, a piece of software which does not have "easy to understand for non-experts" in its design goals. You generally interface through Linux with system call wrappers provided by a libc (or another specialist library for other interfaces like libfuse or libnetfilter or whatever), not directly. Linus is, quite obviously, good at many things; it's silly to assume that means he's an expert at everything.
Linus developed Git as a low-level tool. Linus put a lot of thought and care into getting the implementation details right, but intentionally did not build an easy-to-use interface. The Git command line that people use today ultimately derives from Cogito, a toolkit written by someone not Linus that sat on top of Git. Eventually Git (which Linus had long since handed off to someone else) adopted most of the conventions of Cogito and created a "porcelain"/"plumbing" split. If you think it was arrogant to develop Cogito, I suspect you disagree with Linus.
Finally, Linus develops Linux with a very particular model, with e-mail-based patch reviews, merges from subsystem maintainers, etc. Most projects (even most open-source projects, but certainly almost all proprietary projects) do not work this way. The Linux kernel does not use a GitHub-style workflow for development, which is by far the most common way people outside the kernel community use Git. It may well be the case that a lot of thought was put into making Git work really well for Linus's use case but it does not match how other people do development.
The difference between the kernel development model, and some putative "typical other" development model merely changes which git commands/tools get used to handle getting stuff into a particular branch on the canonical repo.
It has no impact on the underlying concepts that make git scale well, cover 100% and 100% remote cases equally well, and provide deep under-the-hood concepts that can be deployed in exceptional circumstances.
Correct, it has no impact on the internals of Git, which was my point. Git's internals are used by both the kernel development workflow and the GitHub-style workflow, and Linus designed it well.
The conversation is about the user experience of using Git - its CLI design, etc. It is entirely about "merely" what commands are being used. TFA is about new Git commands, not about any changed internals. Or, in the case of Sourcetree, it's about not using any of "Linus's" interface to Git (which, again, wasn't written by Linus) but interacting with the same Git internals.
I think the conversation is about whether or not the Sourcetree interface to git can be useful when carrying out tasks that involve, for example, filtering the reflog.
If you have never done this before, and have only ever used git via the ST interface, switching to the CLI to get this done is going to be quite a shock. Maybe that's OK because realistically such tasks should be rare. But sometimes they are a critical task in development, and finding that the entire dev team is completely intimidated by it can be an issue.
Linux is, very intentionally, a piece of software which does not have "easy to understand for non-experts" in its design goals. You generally interface through Linux with system call wrappers provided by a libc (or another specialist library for other interfaces like libfuse or libnetfilter or whatever), not directly. Linus is, quite obviously, good at many things; it's silly to assume that means he's an expert at everything.
Linus developed Git as a low-level tool. Linus put a lot of thought and care into getting the implementation details right, but intentionally did not build an easy-to-use interface. The Git command line that people use today ultimately derives from Cogito, a toolkit written by someone not Linus that sat on top of Git. Eventually Git (which Linus had long since handed off to someone else) adopted most of the conventions of Cogito and created a "porcelain"/"plumbing" split. If you think it was arrogant to develop Cogito, I suspect you disagree with Linus.
Finally, Linus develops Linux with a very particular model, with e-mail-based patch reviews, merges from subsystem maintainers, etc. Most projects (even most open-source projects, but certainly almost all proprietary projects) do not work this way. The Linux kernel does not use a GitHub-style workflow for development, which is by far the most common way people outside the kernel community use Git. It may well be the case that a lot of thought was put into making Git work really well for Linus's use case but it does not match how other people do development.