This is so true. When I first moved to the Bay Area after finishing college, I was astounded by the amount of recruiter spam I got, but at the time I didn't recognize it as such. To someone who's never seen these before, the initial impression when you see these types of messages is, "Wow, look at all these different companies that want to hire me." Of course you know it's not an actual job offer, but you sort of think in your head, maybe I'll just have to come into the office and have a brief chat with some of the engineers, and then they'll hand me a formal job offer. Because clearly they already recognize your technical aptitude, since they're reaching out to you!
In actuality, once you decide to respond to one of them, you quickly realize that you're not fast-tracked in the application process in any way. Really, the only step that was skipped was that you didn't have to manually apply on the company website. In fact, the application process is usually longer and more difficult in Bay Area companies than elsewhere (at least in my experience), where it's typical to have to do
1. Initial phone call with recruiter
2. One or two algorithm interviews on the phone with an engineer
3. "Take home coding challenge" which they claim only takes an hour or two but often ends up taking you 4 or 5 hours because you don't want to submit subpar code
4. "On-site" interview that can take 4 or 5 hours
Meanwhile the recruiter has no problem lying through their teeth about the details of the role. Like, I've had a number of applications where I tell the recruiter I'm looking for a role that's math/ML focused, only to find out once I get to the final onsite that, no this is just a pure engineering role. They don't care how well your experience or interests fits with the role; all they want is for you to do the interview so their numbers look better.