Dessert Nomad
Adventurer
Again, as experienced players, we know that isn't the case. Nobody has done anything wrong. But, the new player doesn't know that, so they turn to the most experienced player, or the person who seems like they have the most experience and asks what is up. That's generally the DM. They could also turn to the person who brought them to the game, and then that person may talk to the DM.
The comment that I responded to originally directly contradicts what you said here; rather than saying "as experienced players, we know that isn't the case. Nobody has done anything wrong" it explicitly and clearly stated that we 'know' that is the case and that the other player had done something wrong. "Had I been the DM, I would have pointed out to him before game how that stepped on the toes of another player rather heavily, and suggested he take something else." Your long example of a genuinely confused newbie who is wondering stuff is simply not what I have been talking about.
If you think I object to new players who are confused and trying to learn, please quote any instance of me saying anything at all bad about a person new to the game who "asks what is up". What I have objected to is the new player deciding that they own a game concept and declaring that other players are 'stealing', and the explicit endorsement of that concept of 'ownership' of basic game mechanics in the original comment. I have at no point said that there is anything wrong with asking questions to learn about the game, or with feeling confused. What I have a problem with is players who want to decide "I get to be the only warlock, archer, wizard, user of the hex spell, or some other thing" and expect other players to fall in line, and with pandering to that attitude as experessed in the post I originally disagreed with.
Humans undertaking a new experience are, typically, a little unsure and insecure. This is normal, and human, and you should perhaps cut them some slack. It takes time and experience for a player to discover what they find fun in games. If you are not going to be willing to give them some space to do that, then yes, they shouldn't be at their table, but not because of some flaw on their part.
The problem is that what 'cut them some slack' actually refers to is 'tell other players that they are bad for creating the characters they want to create that are worse at a thing the new player does, and set up additional character creation rules to enforce the idea that no other characters can have similar abilities to this person's character'. If another player spending 1/3 of their characters feats they will get by tenth level to gain the ability to do something like what that character does, but distinctly inferior, is a problem for a particular human, then I'm perfectly willing to say that yes, that human has a flaw of being controlling and difficult to get along with.
Oddly enough, I have found that actual people in the real world undertaking a new experience who are a little unsure and insecure don't actually try to tell other people what to do. They end up being cool with 'oh, we're both archers' or 'oh, we do a similar thing but I do it much better and keep getting better at it' once you explain how the game works.
If you are going to brand *new* people with negative personal traits for failing to grasp more advanced game dynamics... they are not the problem in the scenario.
"You aren't the only one who can be an archer, or warlock, or have a particular spell" is not an advanced game dynamic.