what's the big deal with gmo's

Well... Read this extensive review of 1783(!) research documents published from 2002 to 2012 related to the safety of GMO crops.  The review and analysis was performed by a group of Italian scientists at the University of Perugia.

http://www.geneticliteracyproject.org/wp/wp-content/uploads/2013/10/Nicolia-2...

Conclusion:  "We have reviewed the scientific literature on GE crop safety for the last 10 years that catches the scientific consensus matured since GE plants became widely cultivated worldwide, and we can conclude that the scientific research conducted so far has not detected any significant hazard directly connected with the use of GM crops."