This is probably far more common than we'd like to admit.
I've certainly worked in places where they'd rather I didn't get involved in the hiring process. These kind of places often heavily relied on external recruitment, and would rather that I spend my time working on projects than potentially rejecting candidates that could do the job, but weren't up to my standard.
These aren't non-tech companies either - these are companies that deal in/sell tech as a project and/or service. Even in companies that live and die by their development team, non-technical management can run the show and dictate hiring.
I've been a "senior" engineer for years, in that time I've read through a few dozen CVs, sat in on 2 interviews, and had final say in hiring of exactly zero people. I suspect the same is true for at least half the senior people here, unless they also happen to managers.
I'm not trying to sound accusatory, I'm just interested. Aren't you interested in choosing the people the people you're going to have to work with every day? Are managers doing interviews where they're asking technical questions?
I remember myself and every other senior engineer on a team once rejecting a candidate and being overruled by management. The guy was hired and... turned out to be as useless as we thought he'd be.
Well, the person might not have been the most skilled guy around, but how hard did the team worked at integrating this person?
I mean, starting with a negative reputation in a team that felt betrayed by your arrival doesn't seem to be the best condition to give the best out of yourself.
There is infinite opportunity to screw over a new hire. Just getting setup in the dev environment on any team is usually 50% undocumented and you need help from coworkers.... it's one of my least-favorite things to do on a new job.
Also undocumented in large companies: how to get ANYTHING done outside the team.
Then when it comes to reviews, especially in large companies, you are utterly beholden to whether or not your manager likes you. I've only ever seen one person the manager disliked get a glowing review, and the manager did it as a joke since they were quitting.
I certainly have sat in on interviews and think it's valuable experience for a senior, especially when you're looking to fill a particular gap on the team. I was more pointing out that this is a very generic comment around a very complex problem.
At my current company we ask even juniors to get involved. Interviews are in pairs, with at least one senior person in that pair, so we can make sure each interview is as fair as possible. IMO everyone can have a valid view, and since we could well be looking for their next team mate I'd prefer to know that it's not just my opinion that gets heard. It's been working pretty well so far, and given people more experience in hiring that I hope helps them later in their careers.