You can't just "turn on the lights" for outdoor activities except in very specific cases. Those activities can't really be done in the morning because people have to get ready for school/work during that time. I really don't want to waste perfectly good sunlight getting ready for work. Let me use it when it can actually be used.
I would suggest it's because the sun is a far better light, and most people don't have the ability to light up the entire area to make it seem like daytime.
Note: I'm a late-to-bed person myself, so I'm happy about this, but I want to be honest about the fact that my support for it over a permanent no DST is my personal preference being imposed on others. In the US south there's a saying, "don't piss on my leg and tell me it's raining" and I try to honor that here.
I literally say my reasoning in my comment. It's much harder to light up the outdoors for outdoor activities after work/school. I can't use sunlight in the morning for anything other than a wake-up aid.
But regardless, I still disagree. You seem to be assuming that early risers don't want to do outside activities, but that is not true. There are plenty of people that go for a run or jog, or morning hike, etc before work. At a previous company we had a rock climbing club called, "Get High in the Morning" :-D
One of the benefits of living in Utah, great rock climbing was only a 15 to 20 minute drive from the office.