I'm a new rider and I can tell you all of the reasons I bought an '03 Low Rider as my first bike.
1. The Harley dealer offered the Riders Edge class over Memorial Day weekend, which fit my busy work schedule. I liked that.
2. I wanted something I could resell easily if a. I didn't really like riding b. I didn't like the bike I had bought (not knowing much about motorcycles).
3. I wanted to learn to do my own maintenance and wrenching. Just about anyone with youtube and a service manual can do engine work on a Harley. I replaced the cams and upgraded to hydraulic tensioners in the first month with no prior motorcycle mechanical experience. Which leads into...
4. Any issues with Harley's are well documented on the interwebs. I bought my bike knowing the cam tensioners had already been addressed or would need it.
There are probably a lot of other reasons that I've forgotten.