Not like it matters because by your logic them going in for the first time to just try it is almost offensive in your eyes; to the organised groups. And while they may go in with every single intention to pull their own weight, to you they're just there to be carried and to leach. So, instead of showing a more positive outlook about it - you're basically hostile towards them. What kind of image does that paint when you have the premade discord group being hostile and then telling them to 'join a premade/discord group' when all they've seen is the discord group being hostile? You get threads like this and people complaining about the discord groups which make people even less likely to join them.
Nah, if I went in for the first time with the intention of pulling my own weight and then I'm met with hostile people snarling at me to get into discord then guess what, I'm not going to join the discord which has those people in it. Already you've painted them in a bad light; people are going to be dispositioned to be hostile even when they join the discord group. 'Look there's that person who sniped my portal, grrrrr'.
Again those who enter the portals may enter them with innocent intentions and with a mind to actually clear the content and pull their own weight. Why would they assume that discord is needed when up until now, no such coordination is needed and the way SE has set it up is for first come first serve to fill the instance. You can't blame those who are taking the portals without gatekeeping and you have no right to do that.
I haven't seen one person here specifically say 'Wahhh, the organised group isn't carrying me' - OP specifically said that this particular person wanted to group up so they were part of the organised group. They could have invited her and offered the discord link. They didn't. If what OP said is true they effectively blacklisted her.
And from your previous posts, it wouldn't surprise me that any newbie who takes a portal without being part of your premade is also effectively blacklisted - instead of, you know, guiding them. The excuse of 'Oh I tried it once and it didn't work' is dumb.
If you don't like the fact people can take the portals without there being limitations on just who can take them. Then you either need to complain to SE or adjust. And people wonder why SE updated their rules policy - yeah, they saw this coming alright.
While I can totally understand the frustration of losing the spot to another; when people devolve into harassing the person - then yeah, there's a person at fault alright. They shouldn't be surprised or shocked if they're reported for their actions. Just like you can't be surprised or shocked if someone doesn't want to join a voice chat when those same people were hostile to them moments before.
In the end, what you expect is for people to have experience in BA, yet to get experience in BA they need to join a premade or 'snipe' a portal. If they're new to BA after doing previous eureka grinds which didn't need discord communication - then somehow they should automatically know that they need to join a premade and use discord communication to get anywhere. No, that's not how it works. Honestly, people need to see it to believe it. Isn't that how this started in the first place? With everyone randomly going into the portals and trying by full-on pugging? I don't see how this isn't any different - people are still going to go into BA with that kind of mindset - they will eventually learn in a good environment with people willing to help. Just like in every content that is beyond the causal dungeon run.