If Plissken was referring to the 'smalleyed' snakes being discussed in this thread which to me are not necessarily defective, I can see her point. If a snake is kinked or deformed in an obvious way, I don't have anything against euthanizing it, but I don't like the practice of euthanizing otherwise healthy snakes because they are just normals, or lacking the pattern you wanted, or because you just don't have room for that one and you got a morph you'd rather keep in the same clutch. Maybe 'happy snake' is the wrong term, but some things will affect the quality of life for an animal and other things will not. If these small eyed snakes can see fine, eat OK, and have no health issues or other noticeable problems why euthanize them? Because their eyes are a bit too small just doesn't seem like a great reason to cull to me. The small eyes could be related to other 'defects' or maybe not, but you can't assume these things, you would have to keep and observe the snake to know for sure.
I can see the cheap snake point, but not every pet hobbyist is a breeder, why should someone who just wants a pet snake not be able to buy a healthy, but less than perfect or more common specimen inexpensively? If it wasn't for cheap snakes maybe fewer people would be getting into the hobby and going on to buy more expensive ones down the line, that's how I got started.