In my example, it was other kids at my school and their parents protesting it for environmental reasons. And mind you, the powerlines weren't even passing through our town so it wasn't NIMBYism.

Lots of NIMBY anti-development people would consider themselves environmentalist. They are in fact conservatives people that would rather keep the status quo and are against free market for housing and want their assets to inflate to insane prices.

Unsurprisingly.

Moreover, politicians passed unpopular laws e.g. ecotaxes or bans and direct blame onto "environmentalists".

It can be a powerful tactic to drive a wedge between general population and "environmentalists". Ultimately to protect certain companies.