Source: I am a developer like you that has the exact same instinctual attitude about it. Here is why it's wrong.
Project managers need to build schedules so they could coordinate dependent features across multiple teams.
Marketing needs to orchestrate launch announcements and fixed activities that are not quite as inflexible as printing millions of CD-ROMs, but still require dates.
And managers, ultimately, are held responsible for a project delivery, so they need to track it's progress, understand what things are ahead (lol) or behind (yup), which areas need help from more people, more seniority, or less scope.
All of this needs to come together for any successful project of any reasonable complexity.
None of this is new, or news to you, of course. Here's the part you're missing: The way things USED to work was that PMs, Marketing, Sales, and Managers would come up with processes that worked for them, and forced it on development teams, regardless of how it made the devs feel.
Agile was an attempt for the developers to take ownership of their process bottoms-up. Planning poker, standups, sprints, all these ideas were invented by developers to make their lives EASIER not harder. And none of it was supposed to be panacea - the only way to do things. Each team is supposed to figure out the right balance of what works for them.
So don't be apathetic. You are an active contributor to this process. Take pride in the fact that you have a lot of autonomy about how to define your project structure in an agile environment. Change what you don't like, and figure out what works the best for your team.*
* Giant fucking asterix: I understand plenty of companies are extremely top-down and inflexible about "AGILE" development processes. They paid some consultants millions of dollars to define a process, and they're going to force their development teams to follow it regardless of what the front line devs want. If that is what is happening at your org, I'm sorry, that is truly unfortunate. But by and large, I find that even at companies where the devs have plenty of autonomy to define their process, they still grump about the very idea of having be forced to provide status updates or work in atomic chunks of effort and keep their software constantly releasable.