The reason people on here tend to dislike those types of tools is because they've probably been the ones who had to fix the tangles people get themselves into by using those tools. Tools that obscure details in favor of simplicity are fine in some cases, but version control is an inherently complex problem domain where having those details is important.

In my experience mentoring juniors new to git, those who are just given a few basic commands don't create as much of a mess because they don't have the commands required to make a big mess. When they do make a mess, it's usually because they've copy-pasted something from the internet, and most will acknowledge that blind copy-pasting _feels_ wrong. Give them a GUI, and suddenly there are buttons to create all sorts of unholy mangles right at their fingertips.

As a really simple example, one of the most frequent things I see from juniors using git GUIs is adding files to a commit that they didn't intend to (say stuff that's not in the .gitignore, but doesn't belong in the commit). In the CLI, they probably don't know about -a, so they would be forced to add files/directories individually and think about what to include. Most GUIs I've seen include a "Stage All" button front-and-center, which is very tempting for a new user to click (or, worse, they make staging an opt-out thing). I do not know if this specific example is the case in GitHub Desktop, it's something that I see regularly.

I agree with your last point. I think git GUIs are best for users who already know what they're doing and find that a GUI speeds up their workflow.