I think part of the problem in explaining the problem is conflating GMO with hybridization. They are not the same thing at all.
As a farmer, I have several problems with GMO crops.
Some philosophical: patenting GMO seed stocks and then suing farmers whose own non-GMO seeds are contaminated by cross pollination from GMO crops.
Some are practical: ie splicing Bt genes into the DNA of crops is, in my own opinion, and indiscriminate blanket use of a pest control tool that should be used only when pest populations rise to a level, as is determined by regular field scouting, as to warrant its use.
The practical concern is particularly troubling because Bt is rapidly losing its use an effective pest control precisely because it has been used as a blanket preventive instead of on an as needed basis, so the pest are becoming immune.
I could discuss this in more detail, but most of the time people’s eyes start to glaze over.