I would expect that sort of thinking from a 20-something trying to get laid, yes. But Luccio is a grownup, and is supposed to see Harry as the same.
Well, the trying to get laid part was mostly a joke. Although, Luccio was the one to point out what a roomy back seat the Silver Wraith had, so who knows?
Given their background, the respect she supposedly has for him, and the stakes of their world? Yeah, I'd expect the straight truth.
Luccio was telling Harry about
who Maggie was, not just facts about things she'd done. And that was what Harry wanted to know, and because Luccio cared about him, she understood that and was trying to help. Much the same way that Murphy might have done in her place, I'd imagine.
Other people have told Harry, and us, such things as, "Maggie LeFay was acquainted with this person and this person and this person, and she committed this crime," and then they've left it to Harry, and us, to draw our own conclusions from those statements. Luccio is the only one yet to say, "Maggie was like this and like this and like this, and she loved these things, and believed in these things." Luccio is the only one who has given us any information at all about
why Maggie LeFay behaved the way she did, rather than simply pointing out isolated facts and letting us draw our own conclusions from them. Dismissing everything she said just because it seems somehow out of place from your point of view seems like a huge mistake, to me.
Drawing conclusions based entirely on who someone knows and a few things that person has done can lead to terribly flawed results. Here, I can prove it:
"Harry Dresden is acquainted with multiple demons, has summoned a demon on multiple occasions, and struck bargains with this demon more than once. He is intimately acquainted with a Fallen angel, and has received multiple forms of power from that Fallen angel. He is acquainted with several Knights of the Blackened Denarius, has met Denarians several times, and has participated in deals with them on more than one occasion.
Dresden is guilty of breaking the First Law. He has done so at least once, and many on the White Council believe he may have done so more than once. He has summoned a zombie to the certain knowledge of no less than five Wardens, but was able to escape execution by way of a technicality.
He has many times been seen in the company of various members of the White Court, is known to speak an ancient language spoken among their ruling families, and has struck bargains with the ruler of that Court on more than one occasion.
Dresden is known to have had many dealings with the most powerful of the Unseelie fae, and is the personal champion of Mab, the Queen of wicked faeries herself."
--yet all of that would not give someone a very accurate idea of who Harry is at all. Ebenezer, Maggie's father, is the person who taught Harry how to use magic for the right reasons, and what those reasons were. He taught Harry by behaving as an example of the virtues he expected Harry to live by. And yet, Ebenezer is also the Blackstaff, and he has apparently used magic to commit terrible atrocities with magic, in service to the White Council. Both of those behaviors are a true part of who Ebenezer is, despite the fact that they seem to contradict one another.
Given that Harry is as complex as he is, and that Ebenezer seems to be just as complex, why should we expect Eb's daughter, Harry's mother, to be easily defined or simple of nature? According to Luccio, Maggie was at least as smart as Eb or Harry, and maybe smarter. The long-term planning Maggie did on Harry's behalf is a pretty good confirmation of this, in my opinion. So why should she be simple, when neither her son nor her father are?
Also, Luccio's description of Maggie fits what we saw from Maggie's personality imprint in a way that the raw facts from Chauncy or Nicodemus, or even Ebenezer, did not. And since that's the only time we've ever had the chance to see Maggie in action, it seems like one of the more vital sources of information on the subject.