It isn't android. It's the manufacturer skins. AOSP Jellybean runs really smooth on my low end phone. (512 MB ram, 600 MHz processor) But HTC Sense 4 runs like crap.
You may wanna read up on what free software actually is. The free used by the FSF generally denotes that you have access to the source code and are free to modify and redistribute it.
http://uncyclopedia.wikia.com/wiki/Haskell#Haskell_Code_Exam...
It's like using code from the IOCCC to make a point that C code is not maintainable.