I used to think the same thing about women's leagues until I started playing at my current club. They have several women's leagues and more women than I've ever seen playing golf anywhere. The vast majority of them are 55+ and a lot of them are walkers. With all that said, you'd better not dilly-dally in front of them because they don't mess around - they play fast, and they also won't hesitate to bend the marshal's ear (and the golf operations manager's ear after the round) if you were holding them up. If you're playing behind them, you better be moving if you want to keep up with them. I've played some slow rounds behind other groups, but the women's groups have never once been the problem.Really? Someone did a study measuring the amount of time lady's leagues took in and around the greens and did the same for men's leagues? I've never seen such a thing and would be interested if you could point me to such a study. Did they also compare their overall time for a round, or just that portion of each round? As for the second part, I have (sadly) seen a segment of male golfers that accuse women golfers of all kinds of things. So I don't put much stock in comments about women golfers sans evidence.
While not a controlled study, I play a lot of golf, including at times and places that have a lot of women golfers. Overall, I find them very aware of pace of play.
n=1 and YMMV and all, but they're definitely not the problem at our club.