Trail etiquette.. Is this a case of trail ego or did did I do something wrong?

Today I was hiking at Lory and coming down from Howard Trail. If you are familiar with this trail, it is steep, rocky, and has lots of switchbacks. I hike it often—like once or twice a week, sometimes more, for at least the past six years—so I naturally hike a bit fast on it.
Well, today as I was coming down the upper switchbacks, there were two ladies a couple of switches below me. They were hiking at a casual pace and seemed to be stopping a lot, so I eventually caught up to them. Not wanting to crowd them or make them feel uncomfortable, I stayed maybe 15 feet or so behind them. They were aware of my presence because they had kept looking back and had seen me several times when I was on the upper switchbacks, so they knew I was approaching. I stayed behind them for a couple of minutes, thinking they would step aside.
Eventually, I said in the softest and kindest way I could, "Hi, excuse me, would you mind if I pass you please?"
They turned back, looked at me, and appeared to be annoyed. So I said, "I’m sorry, I don’t want to crowd you or make you feel rushed," all while smiling and doing my best to look friendly, because I am a male and I don’t want to make any women feel uncomfortable on the trail.
They stepped aside and let me pass, but as soon as I did, they suddenly picked up their pace drastically and basically "tailgated" me for a bit, to the point where I was almost jogging to create some space. I heard one of them mumble something to the other—it almost seemed like it was about me—but I didn’t quite catch it.
Did I do something wrong here, or was this a case of trail ego? I’ve been replaying it in my head all day trying to analyze what I did wrong.