As a manager/lead who has personally fielded similar concerns from new hires, I understand where Rachel's frustrations come from, specifically with painful onboarding processes. I'm not commenting on Rachel's specific experience, but just in general for those that might feel empowered by her response; I just don't think it's generally appropriate.
The process was surely designed with good intentions, perhaps by committee. And it's been designed to help those that need help.
For those that don't need help, these things suck.
Providing an out for new hires who don't need this handholding is problematic. You can't just make this stuff optional. You don't know what you don't know, and junior devs often think they know more than they do. Too many people would miss information they actually need. I think a senior-level engineer needs to understand this, and be able to cope with the anguish. Sometimes there are actually useful processes in place, but only useful for a select few, but because it's impossible to know who those few are, everyone must go through it.
There are usually ways for anyone to affect change in an organization, but unless you've been specifically hired to make changes, you're going to have to wait a while, and even then, you may never be able to make the changes you really want. But such is life. Figure out what truly matters to you, in the long term, and you'll likely find you'll become much more influential amongst your peers, and even upper management. If you can't change the things that matter to you, don't torture yourself further; it's probably time to move on.
On the flip side: if you just want to work for a smooth-running, well-oiled machine that aligns with your ideals already, good luck on your search!