The issues with blanket application of Glysophate combined with roundup resistant crops are real; application volumes have ballooned and we still don't have a scientific consensus on it's effects on humans. Ignoring, in the immediate, the potential health effects of the molecule, it is also a driving force in the expansion of monoculture techniques rather than more sustainable polycultures.
Monocultural key foodcrops are a long-tail risk to food security. The Irish potato famine, the lightning quick elimination of the Gros Michel clones, etc.
I won't get into the myriad legal issues surrounding Roundup, terminator seeds, etc. but they aren't theoretical either.
This isn't to say there's no benefit from Glyphosate application. It's to say opposition towards it is not driven by scientific illiteracy. Quite the opposite.