Because we want to understand what impact it is?
Residential house emit heat too, but - most of the time - we don't consider them "destroys local ecosystems".. Maybe they do, but we don't treat them as a boolean thing, we try to understand the impact...
> Residential house emit heat too
You are missing the context of the ecosystem - the topic is water ways. Homes aren't raising the temperature of local waterways which can wipe out entire fish and other aquatic populations while encouraging growth of oxygen depleting organisms and algae. Instead of a river or stream you have a dead stinking waterway.
> You are missing the context of the ecosystem
That's one of several reasons why a citation is warranted.