I feel your pain! After spending over 23 years in Silicon Valley, I am connected to a huge number of people in Tech, now including notable CEOs, VCs, and Angels.
So, yes, everyone thinks you can introduce them to anyone in your network simply by requesting it. I’ve always secured the mutual approval first, but years ago I also stopped doing any connections if I can’t vouch for the requesting party.
If I don’t know you and I don’t really understand your intentions, then I simply won’t introduce you to people in my network.