To answer that question first we must understand why environmental activists and union organisers are targetted in the first place. Businesses make money polluting, clearing land etc. They also save money exploiting workers through poor workplace safety, terrible working conditions, low pay etc. It would be an impedance to capital to allow such individual in government to pass laws limiting profits.

In our liberal democractic world, money wins, no matter what the will of the people is or what the long term outcomes are, the owning class wins every time. It's not as if people haven't tried voting for the right person in the past. In many countries there already exist Labour parties established by workers unions. Despite this, business interests always win. Sometimes they throw a few crumbs at the plebs to appease them but it's always big business that dominates.

Another example, remember Barack Obama's election campaign in 2008? Change we can believe in? Then he enters the presidency and bails the banks out during the GFC and continued the war in Iraq. Coca cola hired paramilitaries to kill union organisers in Colombia. Biden campaigned on climate change action and then approved new gas piplines. I can go on and on.

Answering your question is very hard to do in a short reply. There are many books written about the topic. I recommend the following video: https://youtu.be/fcImfx8tunI?si=FfAJzdCq2qFX2RlI

Also, search the text "vote harder" in lemmygrad, it's a meme to mock liberals.