Why would anyone make such a crippled IDE!?!?!

I already looked up libraries for arduino. These are very simplistic consisting of only ONE header file and ONE source file (and some example files and a keyword file). But there is nothing relating to a full blown library that has many dependent header files.

Bullshit. All one has to do is look at any of the core libraries, like Ethernet or SD. Both consist of multiple source and header files, some using C and C++ together.