Most of you guys are not really listing straight techno, alotta tech-house, and techy trance, but no pure Techno.
Take a listen to a set by any of the following to hear the best of the best:
Umek
Dave Clarke
Jeff Mills
Richie Hawtin
As for why do people listen to it...well...uh....maybe...cuz...they like it?
Isnt that why everyone listens to whatever the heck they listen to?
Cuz they enjoy listening to it.
Country music makes me want to hurt people, but I dont question why other people like it
(well, sometimes I do)
For me, techno is a personal alternative to house music (vocally, jump-up house which I cant stand). It can be dark, layered and extremely complex. The Inspector Gadget song you heard is more a commercial type track and somewhat corny which is why it rubbed you the wrong way.
Personally, I like anything "techy"; including intelligent jungle, breaks and experimental/IDM.
Wanna give it a try?
Start with some "minimal techno"-more accessible than the faster BPM really hard stuff.
Richie Hawtin-"Live at the Windsor"
Its a masterpiece.
*Also, if you find you like the more minimal stuff, try out some Ricardo Villalobos. His sets are bananas.