When I say upstream that's technically upstream of upstream - I mean the application repositories. Manjaro has in the past applied their own patches on top and broken functionality. The example that comes to mind is the most heinous one where a Manjaro maintainer patched in three pull requests (including CLOSED ones) and pushed the result to their stable repo: https://source.puri.sm/Librem5/chatty/-/merge_requests/986 https://source.puri.sm/Librem5/chatty/-/merge_requests/1035 https://source.puri.sm/Librem5/chatty/-/merge_requests/1060 https://forum.manjaro.org/t/manjaro-arm-beta25-with-phosh-pinephone-pinephonepro/116529/11 . Applying patches to upstream is not unheard of, but you don't do it without contacting the developer, because they are the ones going to get the bug reports. Manjaro did not notify the developers. It's this recurring trend of unprofessionalism which has tainted Manjaro's reputation, whether it's letting their SSL cert expire FOUR separate times (once, maybe twice is understandable, but more speaks to underlying issues in structure), or applying patches to applications without developer's knowledge and shipping it to users, or the two separate times they DDoSed the AUR servers with a poorly thought out pamac feature, etc..

I give no concrete examples because this all occurred almost two years ago for me at this point. I'm not out to capsize Manjaro or bring about it's demise, so I don't write down every package that breaks for use as ammunition in internet debates. I just want a distro that works for me. Manjaro wasn't that for me so I moved on. You asked why some people don't like Manjaro and I'm simply explaining why.

The AUR issue happened often enough for me to consider it frequent. It happened most often with niche packages, like the various MSP430 toolchain packages which I often needed, but I explicitly remember it happening at least once on fairly mainline packages like cemu (or was it yuzu?).

The problem is not that Manjaro allows you to pick whichever major release kernel you like, but rather that it doesn't account for this in the packaging system. You could be running kernel 6.4 (i.e. not officially supported anymore) and update your packages, resulting in a broken system with no warning. By decoupling the kernel version from the package system Manjaro unleashes a whole new failure mode. This would be fine if they accounted for this in their packaging model, but they don't (because Arch doesn't and it would be too much work to implement and support it themselves, presumably. It sounds quite tough). This tool, which is designed to make the system more stable as you say, actually can make it less stable!

Manjaro was sold to me as 'Beginner Arch', so I don't know what to tell you on that front. I don't think this is at all related to why people dislike Manjaro though: Nobody hates Ubuntu because it's based on Debian, they hate it because of their decisions, like Snaps. Likewise nobody hates Manjaro because it's Arch based, they hate it because of the decisions they've made. Manjaro isn't the only distro getting hate, but it is probably the lowest hanging fruit due to all of the administative fumbles.