@Totalanimefan: Raiding groups tend to be pretty tight-knit, especially when the raiding community as a whole a small (e.g. LOTRO in general, and my server in particular). In other words, barrier to entry to the general raiding scene is somewhat high. Almost all of the groups that run the current raid on high tiers are done behind closed doors. No one will PUG a high tier raid from world chat...like ever. Because when you pick a random person out, majority of the time, the individual has one or more of these issues: insufficient stats, bad gearing, bad skill rotation, incorrect UI, doesn't know the run, can't learn the run efficiently on the fly, no voice chat, no comms etc. On top of that, most raids need a particular group composition, so it helps to set rosters prior and do any last minute PUG/filling in raider-specific channels.
So to set rosters, typically this is done is various Discords. These Discords usually are specific for groups, and groups have varying levels of barrier to entry. Things like, are there slots open for certain roles, does the individual meld well with the rest of the team etc. As far as I know, the group management I've encountered tends to not be particularly well-structured as other games. The ones I've encountered do not do interviews and some don't even do applications. What tends to happen is an individual fills (backup filling a role on-call; not on the roster) a raid for a particular group through a mutual friend of sorts, that individual is deemed competent and proceeds to continue fill or possibly sign up for raids with the group more frequently, and this in turn eventually earns them a spot in the core group. This has a lot to do with luck and timing for the new individual in "getting their name out there".
This is all fine and dandy, but the process that might be touchy, especially if the individual in question wanting to rush to the end of getting into the core group. The first thing about sign ups is that signs ups do not guarantee a spot on the roster. Depending on who's setting the roster, one might need to be closer friends with the raid leader etc. to get onto the roster. This is the first bit that can cause drama. An individual feels like they are always getting passed over on the roster -- that they have to be "friendly" with certain people to get onto a roster. That's what I call social politics. Usually I say this is indicative of poor management since if someone is passed over on a roster, I generally recommend not passing them over on the next sign up, but not everyone is good about doing this and technically you can run your raids however you want. I know guilds generally will prioritize guild members first, and then guild acquaintances for runs, but depending on group competency, the acquaintances may end up on the roster more often if the other newer guild members are weaker in their roles. Again, that contributes to the constant passing-over feelings for some.
That is the second bit that causes drama -- often raid leaders are setting rosters based on group competency, so someone who repeatedly fails to learn mechanics or never gets better at their role/class can get socially blacklisted as an individual that's hard to work with. So now there are prominent members within the raid community who collectively dislike certain players. I call that "inviting drama". It means certain people can't be put in the same group because it'll end up in animosity, in-fighting, blaming, toxicity etc if the run isn't a first-try clean run.
And then there's infighting on how raids "should" be run, what the loot rules are, what the strategy will be etc. These generally are all set prior to even setting up a sign up, but not everyone is clear about expectations of how participants will interact with the group, so that miscommunication also tends to blow up in people's faces.
And then there are other issues of incompetent leadership etc. But that's a whole different bucket of worms :) Thanks for coming to my TedTalk lol