Lets look at the comments in context:
“Every coach when a kid transfers will tell you they [the transfer] wanted more playing time and how they [the coaching staff] could see the writing on the wall,” Auriemma said. “No coach wants to make a kid look bad [in public]. But I kick myself sometimes because when I recruit a kid I know right from the start whether it’s going to work or not.”
...
“If a good player ever left here, you might have to defend why [as a coaching staff],” Auriemma said of possible static with future recruits. “But you don’t have to defend this.”.
The first paragraph has a statement indicative of the intent to to embarrass the player who is transferring. But there are times when even Geno makes mistakes about whether a player he recruits will be successful at UConn (however the word "success" is defined).
Second, Sadie did not put up the numbers to be a "good" player while at UConn. She had plenty of high school accolades, to be sure. Remember, she was ranked 17th by ESPN/Hoopgurlz, 5th by ASGR, 9th by Blue Star, and 8th by Prospects Nation. This was not Diamond DeShields being the National Freshman of the Year, then deciding to transfer. This was not a player who was built up to be a game-changer in high school (e.g., Elena Delle Donne). In other words, while Sadie was a very good high school player and was ranked very high, she was not a "once in a decade" player or in the "exceptionally elite" class.
Had a player like Breanna Stewart, Brittany Griner, Candace Parker, etc. decided to transfer after one semester, THAT would have been something Geno would have had to defend. If a player who was the team's best player decided to leave after a semester (or even after one year, in the case of Diamond DeShields), that is something Geno would have had to explain to future recruits. But Sadie, for all of her accomplishments, was not that player, in terms of high school rating or on-court performance at UConn.
And that is what I think Geno meant.