And we've been genetically modifying crops and livestock for thousands of years (just in a much longer way), nobody complains about that.
Pointing this out often results in the naturalistic fallacy argument. They argue that using breeding to put selective pressure on certain genes, so that a trait is expressed is fine. But somehow because the modern GM food uses gene splicing and introducing the desired gene in to an organism by using a virus is bad. Even though the results are the same, the second method is bad because it's not natural. Rather infuriating.
I'll admit I had to look up "Monsanto." Okay, so they're a company? What's so "evil" about them. I checked their site (I'm sure people decrying GMO would say that I can't trust them or some shit.), and producing more food with fewer resources seems like a GOOD thing.
Also, I'm not sure what's wrong with specialized fertilizer, unless it's like under such strict control that it can't be accessed easily or like, if a company has some kind of monopoly on the soil.
In reality Monsanto isn't more evil than any large corporation, but it's a boogeyman for many people. They sell GM seeds that have been altered to allow the plants to be treated with Roundup(an herbicide manufactured by Monsanto)without worrying about the Roundup damaging the plant. The argument against this is that the use of Roundup Ready seeds will lead to more use of Roundup, and not use methods that are less environmentally damaging, but more time consuming methods of dealing with weeds. I do think this is a legitimate concern, and why I'm not a supporter of this type of GMO.
The boogeyman side of Monsanto is that they'll sue farmers whose crops have RR genes in them if they didn't buy seeds from Monsanto. People argue that crossbreeding between the RR crops and regular crops could end up with farmers being sued. Supporters of this argument point to a case in which Monsanto successfully sued a farmer who had hybrid crops. What they leave out is that it appeared the farmer purposely let his crops get hybridized. In other cases where the hybridization happened non-intentionally Monsanto hasn't won.
There's some legitimate concern to that arugment, but that has more to do with the broken patent and copyright law the US has than with Monsanto being evil. Of course a major corporation is going to defend it's patents and copyrights.
Edit:While I was writing all this Hades made a post with a point that should be addressed.
He is correct that many people raise the issue of needing to buy seeds every year. However that's really a non-issue. For the most part, commercial farmers tend to buy seeds every year regardless if they bought Monsanto's Roundup Ready seeds or regular seeds.