It's also not realistic, given the wheat-to-chaff ratio out there, for a manager to interview all the candidates directly without an elaborate screening process, although the 'get interviewed by some generic programmer who has a cheat sheet for the Hard Questions you are working through on the fly' seems like an anti-pattern. I have talked to all of our groups hires as a near-final step.
There's a valid point in there somewhere, though. The recruiters that Google uses locally, for example, seem clueless enough to not care that their approach is quite offensive to someone who is not junior and/or desperate for a job. For several years, every few months, I got a come-on from our local Google office that seemed to be implying that working for Google was So Neat that I would probably want to drop 2-3 levels down the SE -> Senior SE -> Staff SE -> Senior Staff SE -> Principal Engineer chain, AND I would only have to carry a pager 1 week out of 4 as a Site Reliability Engineer. Well, hey, that sounds like a real step up from running a team doing something I really like at my current employer and getting to dream up SIMD tricks and algorithms all day! I'll get right on that. My very own pager!