Hey, you're not super dense at all for asking these questions. I've never seen Shameless USA, so can't speak to that, but a sponsee can and will call a sponsor for support and to meet to talk. But it will be centred around the framework of the Steps. Members of AA can and do talk and meet each other when they're generally struggling, but the sponsor's role is to guide the sponsee through the Steps. So, for example, someone will approach the person they'd like to sponsor them after a period of time attending AA and ask to be sponsored.
The sponsor will agree, and they'll begin working through the steps, almost certainly starting with Step One, which is We admitted we were powerless over alcohol - that our lives had become unmanageable. For many alcoholics starting in AA, that will seem like an easy one, but a sponsor will ask for more information, written, or in person. It's an exercise, an undertaking, that requires self-reflection and "rigorous honesty at all times. So, the sponsor may ask in what ways had your life become unmanageable? What had been happening that got out of control? What was life like prior to it becoming unmanageable? At this point, your recovery and time in AA is not about sitting in meetings, "sharing" and (theoretically) listening to other members and identifying with their sharing, it's about forensically examining your own life and past behaviours. It's structured, with written materials and guides, along with decades of corporate knowledge and of course peer accepted notions of what's acceptable and what isn't.
Guest has never once indicated what Step she is on, or mentioned how deeply challenging any of the work has been. She's just portrayed AA and sponsors as being like her own private group of empaths to prop her up when she's feeling down, when it is nothing of the sort.
That's a good question about why a sponsor is generally better when it isn't a friend. Friendship could be adversely affected by sponsorship - sponsor/sponsee gives a power dynamic that may be work within a friendship. A friend sponsoring someone may not be as rigorous or challenging as they might otherwise be. Straight men do not generally sponsor straight women and vice versa - it is a position of authority, to a degree, with all of the potential pitfalls that that takes.
If you imagine the sponsor is someone who takes the sponsee through an intensive process of self-reflection and self-examination, through close adherence to a rigid set of Steps, and following traditions which are now over 70 years old, and where the sole focus is on the sponsee changing how they live their life to one where there is no space for dishonesty to the self or to others, and which is designed to empower the sponsee to live life without recourse to alcohol. The last two points are why Guest's portrayal of AA and sponsorship are so problematic: she does not appear to me to have changed her attitudes to online deceptions, or chronic attention seeking, and portraying herself as close to relapse or self-harm suggests she's not progressed in recovery at all. The "life beyond my wildest dreams" thirst posts are delusional, and would be seen as such by anyone with any experience in AA. The hinting at self-harm or lapsing would be seen as failures to adequetely deal with "life on life's terms" and would be seen as a regression into addictive ways of thinking.
Guest may wish to portray AA as a soft, gentle collection of lovely people there to support each other, but it really isn't. It's tough, it's hard, it's confronting. Many people don't get on. Certain sections have strong opinions on the recovery process not shared by others, but what binds everyone, and what I have never seen anyone deviate from, is a total commitment to help people remain abstainate. Guest, if she actually does attend AA, and if she actually does any of the work, is so far removed from serene recovery that I wonder if she's managed to even understand what the fellowship is. For many, Step Two (Came to believe that a Power greater than ourselves could restore us to sanity) is very hard to conceptualise, and a belief that the AA group itself is a "power greater than ourselves" can be a "holding belief" as we continue to work our way into accepting alcohol was more powerful than the alcoholic. Now imagine that someone as loud, needy for attention, and so wrapped up in their own drama is part of that group. It is really unsettling. I don't dislike Jack Monroe, but I don't want her in her current condition anywhere near AA meetings. I think she's a clear and present danger to people desperate for recovery, but also suffering from the self-esteem or confidence to make their voice heard in a space dominated by a semi-famous person lost in their own drama.
That was a very long answer! Hope it helped.