Recruiters will just dishonestly check all the boxes that you're looking for. They don't care if they waste your time with a bad match. They carpet bomb everyone with their 'opportunity' because it's no cost to them.
I'm not so sure. Think of the way OkCupid works: you fill out a bunch of questions and what you're looking for, and an algorithm creates matches. You can of course unilaterally send messages to whomever, but those people don't have to read the messages, they can just look at their algorithmic matches.
If the recruiter puts inaccurate information in the job listing to try to skew the algorithmic match, it actually wouldn't work; their overly-broad job requirements wouldn't be a fit for your more specific list of tech, so it would show up as a poor match. Only candidates and job listings that have very close requirements/provides would show strong matches. In other words, recruiters are not sending you some tailored thing; they can only create job listings, and the matches only show up to you if they happen to match what you list.
You could also add privacy protections so that recruiters actually can't see your profile at all until you click on a job that you like. You still see the matches and recommendations in your e-mail, so they don't even have to reach out to you. A lot of job sites already do this (automatically recommending you to one or more jobs via e-mail) but they don't have the deep profile data we could compose with questions about more than just tech.
If the recruiter puts inaccurate information in the job listing to try to skew the algorithmic match, it actually wouldn't work; their overly-broad job requirements wouldn't be a fit for your more specific list of tech, so it would show up as a poor match. Only candidates and job listings that have very close requirements/provides would show strong matches. In other words, recruiters are not sending you some tailored thing; they can only create job listings, and the matches only show up to you if they happen to match what you list.
You could also add privacy protections so that recruiters actually can't see your profile at all until you click on a job that you like. You still see the matches and recommendations in your e-mail, so they don't even have to reach out to you. A lot of job sites already do this (automatically recommending you to one or more jobs via e-mail) but they don't have the deep profile data we could compose with questions about more than just tech.