The bottom line is energy consumption. If something consumes more energy to recycle, it is better not to do it. We can add the permutation of toxic materials. We should recycle things that may cause damage.
However, recycling sometimes makes no sense. For example, recycling of office paper is worse than a waste of time. It takes more energy to recycle than to make fresh paper, and since most paper is made from pulp thinned from sustainably grown trees, paper production HELPS forest health.
Glass is inert, like sand. It causes no trouble to the environment. If it takes more energy to recycle glass than it does to dump it, we should dump it.
Recycling as become a kind of act of religious faith. It is past time we figured out when it is a plus for the environment and when it is a liability.
BTW – the biggest sin in recycling is when municipal sewage waste is put into landfill instead of being recycled into fields and forests. Strangely, this elicits almost no protests. In fact, many fight the deposition of biosolids. This is ignorant.
Reference – http://www.wsj.com/articles/high-costs-put-cracks-in-glass-recycling-programs-1429695003