I could really say 'suck', or 'don't care' or 'can't grasp' about it; It's this simple deal that, the people that like OSS or Linux seem to just not get user experience, everything about some software has to be about which language it is written, which package it uses, which code style it uses and so on, but almost never about the actual usability to the person that is going to use it.

It's more than visuals

Specially Linux people seem to think that user experience only means visuals, and spend lots of times making and remaking DEs to look like Windows or specially Mac, and say "here, just like it, you can come to Linux now", while completely missing the point. People don't just use these things for the fancy UI, it's about the functionality they provide, people don't use Mac just for the dock and global menu; it's about how well programs integrate with the system design and functionality wise (no GTK and Qt programs looking and behaving differently), it's about the polish, it's about how it simplifies tasks so you don't need to constantly look at forum posts to know how to do something (appe script/automator vs bash script), it's about not worrying about drivers, so on; It's about the details that on their own are small, but along the use of the system, they stack up, and if the details are mostly issues, the the experience will end up being bad, even if the big fancy stuff is good.

Hobby project vs. actual tool

This whole idea of, 'this open source thing is times better than this proprietary commercial thing, you should use it!', then when someone responds with 'well, does it have the same stability and consistency? does it have small details that make my workflow better? can I count on it to have all the things I need?' and the open source people be like 'calm down it's just a hobby project made on free time, don't expect it to be all this'.

Which one is it? You can't claim that it's both a 'pet project' that is being worked from time to time with no serious vision put into it, while at te same time saying it is a direct competition to something that has actual polish and though put into it. I'm not saying OS programs can't be like this, Blender is an example of serious good competiion by a FOSS program... that has a whole foundation and donations by giant companies behind it and is worked on all the time, most FOSS programs aren't Blender, they are hobby pet projects made with free time which want to both be and not be taken seriously.

It's my way or the highway

Mainly the Linux people thing of complaining why don't more people use Linux, then every time someone proposes to make Linux more user friendly (graphical tools, simplified tools, more automated tasks) they go "no, that's not the UNIX philisophy(even if GNU already isn't), that is too bloated and brain dead, if someone wants to use Linux, they need to learn Vim, they need to know how to solve package dependencies, they should know how to patch and compile programs, else they should go back to soyboy Windows".

It's not even that hard

Haiku, the operating system that started as being simply a revival of BeOS, even though it hasn't left even Beta, it already has polish leagues better than most Linux distros. A simple file system, a single consistent UI, not needing to go to the terminal to tweak things, straighforward usability, all while being a lot lighter than most distors that have the same goal of being user friendly.

Though I have to say that when your entire operating system's goal is that it is a revival of an old OS and nothing more, it's not a very promissing long term goal to be relevant, at some point they need to say 'we aren't just a BeOS revival project, we are our own project with our own distinctions from now own, here are the new features we plan to add', and I hope that when the day comes, they have learned something and don't fall on the same trappings Linux has has fell (we need a gazillion half baked forks, with a gazillion half baked UIs, with a gazillion half baked APIs, all barely compatible with each other, etc).