This is very definitely a safety design.
What you will find is a feature known as "auto reverse", this means when the window is going up if a obstruction is detected it will sense it and go back down.
In America this feature was/is required with vehicles that have "one touch up" (what you have described). I have found several sources saying this is currently being reviewed (2012) but I can't find anything to see if this law has been retracted. The reason they were trying to retract it is because even with the auto reverse people were still being seriously injured, so still the safest option is not to have the "one touch up" option at all.
The reason you have it on the drivers side is actually again a safety feature, it allows the driver to return their hands to the steering wheel. The reason it is not on the passenger windows I imagine is due to cost of placing it on all windows.
It is also worth noting that the placement of window switches and the types of switches is something that has been scrutinised as certain placements and designs have been blamed in cases of injury or even death.
This NHTSA document has a lot of information about US laws (2004) it is very long and wordy so I haven't read it but should cover any points!
Lastly: I understand you are in Europe (as am I) so these US documents aren't neccessarily applicable but they should answer all your questions and provide enough reasoning for not offering one touch up on passenger windows in your region!