Have you tried asking? The Linux Mint community is very open about discussing how even the more exotic components of the OS work, and the developers have a clear set of guidelines they work within and communicate clearly any changes that are made. They operate with the understanding that a lot of their users don't understand Linux very well and will react extremely negatively to unpredictable actions and unexpected changes.
I don't think it's that people can't learn how things are actually being done underneath. It's that these are actually anything but simple. And understanding what is going on is much easier when you are basically handed a blank slate, that is a bootable system with a kernel, an init, a shell and the coreutils, and you add the things you want yourself. Just by the nature of you setting it up yourself you understand at least to some level what's happening, and why. This is obviously only important to people that actually care about understanding the in's and outs of what they are using, and not everyone needs to know, or cares to know what's happening on the computer.
That's just one aspect of it. The other aspect, is like what
@Ferryman was talking about with his guix setup. Once you have a system that you set up yourself, that works in the exact way you understand, and feel comfortable with, it's really hard to go from that, to something that was put together by someone else to work for as many people as possible. It's feels like you are putting a shoe on the wrong foot or something (idk I could probably find a better analogy). After you are used to having something that works perfectly with the way your brain works, and with the way you use your computer. If you are someone that intents to set your computer up like this you can take something like mint, or some other already put together distro, and turn it into whatever you want, but at that point why would you? It is legitamately more work at a certain point to undo what someone else did, to then redo it how you want it, and it usually means you are going to be fighting against the choices that were already made for you on some level.
There's also another plus to a simpler system, that was put together with only the things you wanted. With less going on, generally there are fewer places for things to fail, and when something does go wrong, if you have some understanding of what's happening on your system, it's not too hard to fix it yourself. A lot of the time you won't need to even ask anyone. At most it will be googling an error message, and taking it from there. But I find it's a lot rarer that I have any problems at all on a system that only has what I absolutely need. Fewer programs running, means less code is running, less code, is less bugs. It doesn't matter what OS it is, if there is code there are bugs. And cutting out what isn't necessary is generally a good way to avoid headaches you might otherwise deal with.
All that is just an explanation of why people like the simpler distros. The voids, the arches, the alpines. Obviously there are a lot of people that won't see anything appealing about any of that. But I don't think I will ever go back to something like mint for myself. It's still the distro I recommend to people moving to linux, and I've personally installed it a few times on normies computers for them.