Just some advice
You can use Garageband, and still make original music. Just don't use pre-made loops or Magic Garageband *cough*this song*cough*. Use the musical keyboard tool, and create your own synths, or better yet, record something yourself. Don't blame your lack of program options (which you don't have in the first place) for being targeted.
A piece of advice.
If you don't want the criticism, just switch programs and stop placing yourself in a position where people can easily target you. Yes you might have sampled the song, but it's distorted and sounds quite bad. Again, sounds like loops. Not necessarily a bad thing, but loops are supposed to be a background beat.
Drum and Bass artists use loops for the background on top of their own patters to fill and spice up their tracks. Some dance artists like myself use hihat loops to variate the percussion a bit.
Try branching off onto better programs and furthering your skill. I can see you've got some good ideas, but GarageBand can only take you so far. Might I recommend looking into Reason or ProTools?
My programs are limited as a mac user. I have some programs im working on thought that aren't at crappy.
Please contact me if you would like to use this in a project. We can discuss the details.