According to the text, the use of the expression “clean coal” might infuriate ecologists.
This idea is explicit in:
these euphemisms are “swindles” and “perversions” (l. 32)
The term just doesn’t seem sincere. (l. 37)
It’s a red rag to any green. (l. 37)
A clearer term would be less provocative. (l. 38-39)