|I have this horrible suspicion that he's trying to be funny.|
A better answer is that Christianity is more properly focused on us in our relations with God and other people. Proper stewardship of the earth, though not an irrelevant topic, is quite a bit removed from the “ground zero” of divine revelation and apostolic tradition.
Some Christians are against genetic modification; for instance, a fellow Catholic who contributes frequently to The Distributist Review, John Médaille, opposes GMOs. But I think it’s safe to say that the bulk of Christians who oppose GMOs can and do so without dragging the Lord’s name into it. An argument against GM foods could probably be made from Leviticus 19:19 (“You shall not let your cattle breed with a different kind; you shall not sow your field with two kinds of seed; nor shall there come upon you a garment of cloth made of two kinds of stuff”). However, as I’ve noted elsewhere, Christians aren’t bound to observe the Law of Moses; ritual purity is less important than compassion and avoidance of sin.
For my own part, I’ve not read enough of the relevant literature to take a stand either way. But to slam GMO’s opponents as “anti-science” is both wrong and misleading. Monsanto is the main target, but the agro-biotech giant is also the symbol of corporate regulatory capture of federal watchdog agencies. The fear isn’t of science or technology per se, but rather of “science for hire” — the insidious influence over scientific research wielded by the dreaded, dreadful “one-percenters”.