Lena was absolutely right though about Kara's unprofessional behavior. In the real world, Kara's absenteeism and poor attitude would have gotten her fired a long time ago.
The difference here is that her boss--James--understands her distracted behavior and has voiced true concern, not trying to artificially bond to Kara like Lena. She's just a bank account with ulterior motives, and barked at Kara for being shut out of her personal life. If Kara spilled out her issues with tear-rimmed eyes, Lena would not cop that snake attitude and instantly become just as "unprofessional" in trying to bond with Kara.