You must have been in a pretty remarkable situation timewise, because I've been in 2 (EU) raid training discords and they really offer a lot of trainings on a variety of different moments. There definitely IS gatekeeping in raids/strikes CMs and it can be tricky to navigate and frustrating at times but it's certainly very much possible to start raiding without a guardian angel. I came back after a 4y break a couple of months ago and learned the w5-7 raids purely through LFG with non-kp and training runs.
As I said, seeing a lot of 50KP groups can be a little frustrating but it's also entirely normal to me. Experienced raiders who are about to do Dhuum for the 30th time don't want to wipe for 2h every time teaching new people the mechanics. Sometimes I join chill, non kp groups and enjoy myself but I also often don't have endless amounts of time and look for experienced groups because I just want a fast clear.
In an ideal world you could just write "experienced" and only people who actually know their role well would join and you'd have high success rates but sadly people just lie to their teeth en masse and people who have no clue what they're doing join the run and fail. Only in sth like the HS discord does that really work cause there's an element of social consequences. So the alternative is risk limitation with kp.
I very much disagree with the idea of raids being toxic. The gatekeeping element is present but that to me is not toxicity at all. If you dont join a 50kp group when you dont have 50kp, there is no "toxicity" at all. Generally if people feel like the run isnt going anywhere they'll leave, but rarely do people really start arguing or calling eachother names. People also falsely have the idea that if you dont bring the absolute ultimate build and dps rotation that you'll get kicked. Nothing is further from the truth. As long as you don't ge below an abslute bottom of performance, people dont care. You often see 3 scourges in a group, 1 doing 30k, 1 27k and 1 22k. The truth is that the 22k is performing quite poorly but if you dont drop below like 19k, people just dont care.