Now, by my logic, if they contact me first, shouldn't they already
have a match in mind?
Yes. They most likely have several positions they are trying to fill, and your online presence matched the right keywords in their search.
How can it change in the middle of the process?
It's possible they were jumping the gun and looking for potential candidates while a complete picture of the job requirements was still being developed. But most likely the positions didn't change.
One thing that did change is that they learned more about you "after a few calls and talks/additional details". At that point, they may simply have concluded that you weren't actually the best match for the positions.
Your online resume/CV/LinkedIn represents you to anyone who wishes to do a quick search. So it's very cheap and easy for recruiters to use that as an initial screen. Yet while it may be perfectly detailed and honest, your resume is not you. At best it can only show a small part of you.
If you match the initial search, sometimes recruiters will dig a little deeper by reaching out and determining more details, such as
- Are you actively looking for a new job or have you just parked your resume "just in case"
- Do you really want a new position similar to the ones they are trying to fill
- Do you really meet the full list of their criteria
- Does your personality match the culture of the company
- Are you in the target salary range
- Anything else that isn't present on your resume/CV/LinkedIn that is relevant for the positions they are trying to fill
Perhaps you just didn't happen to meet the full criteria at this time.
Or are these simply some sort of dataminers and not real recruiters?
It's possible, although there's not a lot of value in this sort of "datamining".
What is this all about? It gives off a very bad impression to me about
them and the companies they represent. Surely that is not their goal?
Clearly their goal is not to give you a bad impression.
Almost certainly their goal is to find the right candidates for the companies they represent as quickly as they can.
The fact that they made the first contact with you, rather you contacting them, may be new to you and causing you to feel uneasy about it. But this method of finding candidates is somewhat common these days.
Just as attending an interview but not landing the position doesn't mean the interviewer had bad intentions, contacting you but then concluding you aren't a match doesn't mean the recruiter did anything wrong. That's just the way these things go sometimes.