Sadly once a team scales up past a certain size its not practical to have developers also going out, finding out what people want built, and handling all the feedback on that. You need someone (or a team of someones) gathering the often conflicting requests coming in, and prioritising them against each other.

Having said that, I do believe once a piece of work makes it to a point where people are likely to start working on it the developers who will be doing that work should be involved in the process. They should understand not only what is being requested, but also why its being requested, in my experience that often results in them suggesting alternative solutions that either bet solve the problem, or provide a 90% solution with significantly less cost. It also gives them the context needed when deciding on technical trade-offs involved in different design choices.

How exactly does agile prevent you from talking to your teammates and getting feedback from them?

I get it, but it's now how I do my best work, proxying questions and discussions through a gatekeeper.

Regarding decision-making, that can be a problem---some PMs and product owners are micromanagers, hamstringing their team. But they would be micro managers with or without agile.

Scrum processes are just a way to ensure that no stakeholder, including team members, is left out of those talks, left in the dark, or left unheard. Having a clique single-handedly and unilaterally dictating changes without communicating them or listening to any stakeholder doesn't serve anyone's interests. That's how projects fail.

True. Scrum is a floor, not a ceiling. Nothing prevents the team from going above and beyond the daily standup and the sprint review in terms of communication, and I've never been on a team that didn't communicate a lot more than that. But doing that standup every day ensures that there is at least a minimum of communication, every day.

Part of little-a agile is making changes and adapting -- it's literally in the name. If you have a process in place that prevents you talking to the people you need to talk to, change or delete the process.

I am the same way. I much prefer talking to users directly and come up with a solution instead of having a middle man. But I have noticed that a lot of devs much prefer somebody filtering things for them. I guess to each his own...