People who complain about being gatekept have probably never played an mmo before, because its literally just human nature. The only problem with Lost Ark's gatekeeping is that unlike other games, like WoW for example (using this because I've played it a lot at pretty much the highest level), there's no easy way to tell who is a legitimately good player because there are no logs or parses, so theres no great metric to gatekeep off of. Whales, nerds who suck but do menial shit all day long to get a high roster, etc, look just as good or better than some of the actual good players on paper.
To add to the problem, there are no dps meters or logs (which I do agree has benefits), but at the same time it sucks that you can't see things like synergy uptime or dps, so it's obviously really hard to tell if someone is underperforming unless they're literally wiping the raid or spending most their time on the floor. This makes it feel inherently less fair for good players who don't have the time to sink to develop their character's "resume", which definitely sucks.
With that being said, I'm not going to dedicate extra hours of my time every week inviting anyone for the sake of building up and supporting the community, that's the developers job to worry about. If you wanna do that and it makes you feel good then go for it, but personally I work full time at my own job in a mental health field and I have meaningful relationships with real people I interact with on a regular basis, this is my free time and I'm going to spend it in a way that makes me happy. I couldn't give 2 shits about the upset feelings of random 1 and random 2 after I decline them from my party for not being up to my standards. I have shit to do, I'm nice to the people I run with and I always pull my weight. I make my groups and don't think twice about the people I choose not to run with lol.
People who hate on gatekeeping need to just take the initiative to change their situation, and if they don't think doing that is worth it, and if being gatekept is that upsetting to them, then they should quit, simple as that. I'm never going to want to run with people like that anyway, so whatever, makes no difference to me.