Inquiries in matchmaking – and for the Shar

In the
Hello Rabbi,
I wanted to ask, I encountered a puzzling phenomenon and I wanted to ask whether it is halachically and morally permissible,
Is it possible to conduct a very serious investigation into a guy, both from the content of the questions and the number of inquiries:

• Pointing questions, less "whether" questions but "where," "how much," "how is it expressed." And cross-referencing previous information, "I heard that so and so" with the information you brought up and trying to reconcile them.
• The number of participants, an obsessive search for friends and people who met and taught him from yeshiva high school, and so on and so forth.

When it turns out that the guy was completely unaware and did not give his consent for this investigation.
To me personally, it sounds excessive that when there is no concrete information that the guy is interested in the proposal (and has actually given his consent) to the move, it is possible to inquire about it like this.
The thing is, I was introduced to a rabbi who is also an important "educationalist" who did this. And I wanted to ask if this is permissible?
 
PS
I'm one of the people who asked him questions, but because of all the clever questions, I made the guy look like a total jerk, while in reality he's really cool. For example, let's say he came off as such a fool because I didn't know how to explain how his intelligence was expressed. And when I thought about it, I can't find a way to explain to other normal people, except for all sorts of geniuses or weirdos. While he's normal..