libre office was made because development on openoffice stopped or was held back by oracle. so libre office first fixed plenty of bugs from openoffice, improved compatibility with MS office and added a few new features. so yeah there is a difference between them.OpenOffice 3.4 is not only the best office suite for Linux, but a good office suite by any standard.
Try to uninstall explorer in windows. also remove word pad. see if it's easy.I use it by choice and I still wouldn't want that forced on me or on anyone else. Windows doesn't force an office suite down my throat (you can uninstall MS Office if you don't like it - I have), so why does Ubuntu feel it has to control that aspect of my experience? I thought Ubuntu was about choice...
you are correct. hence the mini.iso. installs basic os, you add what you need to it and that's it. you can use command line only (no GUI), if you want to. you can also remove drivers and modules you don't need from kernel and compile your own mini kernel that works only on your maschine. so many choices....An OS can function just fine without a word processor, a web browser, or whatever. It all depends on what you want to do with it.
but that's not the point here. the point is that people want an OS that is easy to install and has many things preinstalled for them (inlducing media player, browser, office suite, emailclient, IM porgramme...). which is why many use Ubuntu (or Mint which has even more stuff preinstalled).