I think the difference between doping in cycling and doping in other sports is that cycling is a 99% physical sport, soccer for example it does not matter that much whether you can run fast as long as you know how to play well. Formula 1, golf, tennis, even swimming require a technic. you can be very fit but you NEED to master that technic. Look at tennis for example, Federer is not the strongest guy, but he has such natural talent that allows him to sometimes defeat a beast like Nadal.
Now, Cycling is different becuase technic is not that important. The problem with cycling is that unlike most other sports, right now, it does not matter how much talent you have, because if you don't dope, you can not compete. This was not the case before EPO entered the scene in the early 90's. In the 60s, 70s, and 80s, doping existed as well, but it did not make life impossible to honest people with talent. They had a chance before, but not now. That's the big problem.
In every aspect in life not only sports, there is always people trying to cheat, OK that's life. But could you imagine for example that all policemen, or all teachers, or all, enginners were corrupt cheaters??? Well, that currently happens in cycling and it is sad.