The men have a shorter qualifying window, so perhaps a bit of a greater sense of urgency there. Also, men are allowed to qualify via 5000m times, women are not. I doubt the respective men's and women's qualifying times reflect a relation to the World or American records for the events, it likely has more to do with how those times show up on annual performance lists in recent years and the desired field sizes at the trials races. Any relationship to any record and even that they may serve as motivation for runners is purely coincidental and not necessarily the intended outcome of the trials races. If the women's standard is statistically softer than the men's, that is simply a reflection on the fact that the women's side of the sport is competitively not as strong as the men's.