To be fair, I don't think I've seen most geoengineering techniques, especially the sulfur reflective particles one, presented as not being ecologically disastrous (though the particular damage I've previously seen it suggested as likely to cause was different). I've usually seen that presented in a "thing to consider if the consequences of warming becomes worse than the consequences of simulating a long term volcanic winter" context, in which case, pointing out that these ideas cause other damage and that their effect isn't to just revert the climate to what it was isn't really "debunking" them, it's just presenting a better picture of what the potential costs and benefits actually are.