is soldering necessary for a robotics and electronics hobbyist?
No soldering is not required. 

Robotics and electronics is a huge area. I know people that haven't touched an soldering iron in years because their job does not require them to do so because the field of robotics and electronics is so large.

However, depending on what your interests are and what your current level is, you may have to get your hands dirty and get into the low level stuff, such as soldering. If this is of no interest to you, then you are looking at paying someone else to make custom cables and any other assembly work you require. If time and money are of no concern to you, pay someone else to do it. Problem solved.

Though, in my opinion, learn to solder. Read up on whatever it is that is worrying you, and read about proper techniques and tools to ease yourself. It's a basic skill in this field, and you are only robbing yourself of the basic skill by avoiding it.