It has some effect and if you want a big change sometimes it's better to start small. For example, if you wanted to get in shape you start by running a small distance.
"In other words it serves only to be divisive and give an opportunity for people to have strong opinions about something irrelevant; which is actually the point of much of politics, cement your support base by getting people riled up about inconsequential and thus risk free issues."
This is even more disturbing; you think that people on the left (and yes I'm just going to name the sides here) want to help the environment solely to anger the right? I have never met anyone who cares about the environment admitting to me their only and true motive is to anger the opposition.
Is the reason you think this because that's your motive? For example "owning the libs". It is because you can't possibility be wrong about environmental policies that the other side must have another motive?
Do pickup truck owners roll coal on cyclists because they think cyclists are out there riding just to shove that fact in their face? That they are putting all that physical effort as virtue signaling?