That isn't why, and unfair IMHO. Believe me - I'm no Mulkey fan but...
Kim Mulkey defends LSU's traditionally lighter nonconference schedules by stating she knows her team best, uses early games for evaluation, and focuses on preparing for tough SEC play and the NCAA Tournament, emphasizing that her proven success with this strategy silences critics who question the "soft" scheduling. She rejects outside opinions from TV or the NCAA Committee, prioritizing the internal development of her team through dominant wins to build confidence.
I also recall reading that she likes her players to take some time off in the summer instead of playing hoops 365, but I can't find that anywhere so I'm not sure if it's one of her reasons.
Also Kentucky is no slouch and losing on a last second 3 point bomb isn't exactly a disaster. I do believe LSU will probably lose 4-5 other games in the SEC, but they are a top 20 team for sure.