I'm speaking to matt608 of the opinions of people who think of environmental activists as kooks. Continuing to act in a manner that disregards their rights, property and views while claiming an educated high ground is only going to perpetuate, or worsen, their the activists' standing in society.
For that reason, activists being more conscious of the impact that their attitudes and actions have would help. The "treehuggers" could acknowledge that should they get their way, they'll put people out of a job and make their life immediately worse, with nothing of real benefit gained within their lifetime, in the view of those impacted at least.
I'm certainly not in favour of deliberately doing things that violate rights such as property rights, unless there is good reason to do so, most activists I think would agree. For example, fracking. I don't know what your stance is on fracking but its been scientifically proven to poison ground water, pollute the air locally and release large amounts of green house gasses, as well as cause earthquakes, release radiation that was previously stored underground in the rocks, and permanently pollute huge amounts of water used in the hydraulic fracturing process.
Given these facts, many activists would say that setting up a fracking rig near someone's home violates their rights, because it physically attacks them. If someone was setting off a chemical weapon with these effects we would call it a terrorist attack. So an activist chaining themselves to the gate or blocking the road to the fracking site is well within their rights, because actually, the frackers are violating the rigts of the local people and the activists is defending their rights. If the system was working properly fracking would be illegal, as it is in many countries.
This is what I mean when I say the activists are often well educated and informed on the matter they are protesting agains. They know that whatever it is they are protesting against is a violation of rights, and they are prepared to violate 'lesser rights' in order to protect the more import basic rights, such as the right to clean drinking water, or the right to clean air.
If someone loses their job and their job was to destroy the local environment and make climate change more severe for the profit of massive corporations, it's a good thing that they lose their job.
But the problem starts out right away. "Unless there is good reason to do so."
From the perspective of many, there isn't good reason for most environmental proposals, and because environmentalists are generally perceived as spending more time forcing their opinion onto others than proving the case that something is good or bad, people get quite angry with them.
It might help if you delineate between pollution issues and others in your mind. Again, most people are on board with stopping pollution. But the public image of environmentalists is NOT of courageous people stopping the powerful from polluting on innocent people's property. Not by a long shot. Using that aspect of activism as a starting point is going to lead you astray if you really want to know what's behind this study's results; to address the image problem, you have to address the actual intrusions of environmental activists into private affairs (i.e., no third party [EDIT: as in a *person*] is getting their property, food, water or air damaged.)