Agree with everything you've said, especially the one-and-done thing for the Emboldened mode.
I used to think raids were exclusive and elitist, but as I just got into raiding myself a month ago with no issues, that really isn't the case. Reason why people get kicked is for not knowing mechanics; I've seen plenty when people join experienced groups when they're clearly not experienced and refuse to listen to instructions. Also seen and joined plenty of training groups up for raids with super patient commanders, so the tools are there to get into raiding. That's how I got into them. It's up to the player to at least know their class a bit, get proper gear, and take the time to read a guide or watch a video. It's a no-brainer why people want specific things for content that only allow 10 people. If you don't want to bring certain roles into someone else's group, make your own.
Surprised to even see people complaining about CM strikes or having LI and KP requirements. Where are you struggling to find groups on LFG for strikes lol? Groups asking for certain roles on normal mode just want to have a smooth, fast clear through strikes, but there are often many "all welcome" groups, especially for daily runs. Been in and led plenty of IBS Fast 5 strikes, as well as helped people learn the mechanics. There are waaaay more groups up without LI or KP requirements; I run IBS Fast 5 daily and see daily groups up without reqs, many at reset. Again, if you don't like what's up on LFG, or don't want to bring roles asked for, take the time to check out the content yourself, get a group of people who want to learn as well, and make your own group.
People who want to complain about raids being inaccessible and toxic aren't making the effort themselves to put together their own group, join a training group, or take time to learn raids themselves. It's not that difficult, but no one in exp groups is going to want to carry people who don't put in any effort themselves.