The question was not "Is a guru necessary?"
I do not at all doubt that a guru is necessary.
The question was about how to choose a particular guru - whether to go for Swami X or Swami Y or Swami Z (or Roshi A, Roshi B, or Father D or Reverend G?), and how to justify that choice.
Even within one tradition, the situation is everything but homogenous. Different teachers have at least slightly different teachings, different moods, different reputations, and different kinds of pressure exist in relation to each teacher.
I might personally not like a particular guru - but perhaps he has the most accurate knowledge of the Dharma, it's just that I do not know that, given that I don't particularly like him and don't spend much time reading/listening to him.
Like most other relationships, the medium it is formed through is communication (or sravanam kirtanam, if you want to get specific about gurus). As for exactly who we form a relationship with, that is similarly complex. For instance a two people can spend all day talking about how they hate their partner, but one is on the brink of filing for divorce and the other wouldn't consider it in their wildest dreams (although admittedly divorce isn't such a wild option given the current social climate).
IOW even if one draws up a checklist of characteristics of people we draw relationships with, we find that probably most of the people who we are actually friendly with have some (or many) characteristics that stand outside of such a list.
IOW such a discussion (of similarity) revolves around general principles and not details.
I have already experienced that talking about the same problem with different instructors can result in getting very different instructions.
One can also get very different instructions from medical practitioners .. yet they can all be categorized under the banner of professionals who work in the medical field (aimed at increasing one's medical benefit ... just so we can exclude the snake oil peddlers or what have you).
And that said, it all begins at the point of our having faith that such a person is acting in our best interests - that's what gives them the leverage for us to take up their advice.
Especially since the general point being made is that to a materially conditioned person (like myself), the mode of goodness is like sugar to a jaundiced person - unappealing. Does this mean that whatever I find unappealing, this is what I should take up? The more miserable I feel at doing something, the more I should do it?
My experience is that a guru speaks only generally to their disciples until a strong bond is created. That's because the act of instructing in situations otherwise is like water off a ducks back.
It tends to be that the neophyte has an artificial estimation on the reserves of surrender that they have for a guru (a lot of disciples are like shooting stars - spend about 2/4 years in the hot seat and then they disappear off the radar)
How did you know which guru to choose?
Was it somehow never an issue for you?
Did you "just know" which guru is the right one for you, so there was no question choosing among them?
Or did you have such trust in all the initiating gurus that you were convinced that any one of them would be good enough, so you simply took initiation as soon as you fulfilled the formal requirements for it, with whomever was giving initation at the time?
(Or did you get initiated at the time when the "zonal acharya system" was in place, so you had no real choice in whom to take initiation from?)
I chose to take initiation from a guru who had only a handful of disciples. Over a period of about 12 years he had about 10 disciples (just recently he has started initiating more - I think the number is about 400 - most of whom took shelter over the past 5 years) - practically everyone didn't recommend such an option, so I thought about it quite a lot. I took initiation about 5 years after initially asking.
Basically you are looking for someone who can convince you of the importance of spiritual life, so a whole lot of things come in to play - eg how their personal life strikes you, how they can answer your questions, how they feel about you, etc.
And if it was a non-issue for you, could you tell some more about it - what were the qualities that you had, what were your circumstances, what certainties you had that in your estimation most significantly contributed to your choice of guru not being an issue for you?
Moreover, how were you sure, apparently from early on, that your understanding of the spiritual literature is correct, or at least satisfactory - so that you were confident to proceed on the path as you understood it to be - ?
Actually its persons who feel that their understanding of spiritual literature is adequate who never take a guru (although sometimes there is a strange competitive thing where an - apparent - disciple will try and take initiation of a guru just to show him how much they know about spiritual life :shrug: ) ... IOW to understand that one is in ignorance requires a little bit of knowledge.