Earlier quoted context omitted.
Pro cycling is already a pretty dangerous sport, both on track and on the road. To mitigate those dangers a very important part is having a maneuverable bike. Recumbents are nothing of the sort. I doubt that any pro-cyclist wants the speed advantages of one if it means that cornering is more difficult, veering into dangerous.
There are also clear safety advantages to recumbents, like harder breaking without flipping over and an unobstructed view without sacrificing aerodynamics, so I do not think they should automatically be considered less safe. I am also pretty confident that the 'manoeuvrability' disadvantage is completely irrelevant for any individual track event. And do you think that it would be an important factor for time trials?
[edit] And yes, for time trials recumbents would be nice, but already time-trial bikes are pretty different and unsafe, I don't think the UCI would allow even more risk.