That's about the shape of it, yes.

They grew out of movements opposing nuclear power in the 60s, for various reasons (some of the weapons proliferation concerns were valid enough then, though a detailed understanding of fuel cycles and what does/doesn't generate usable weapons material seldom factors into the objections).

As the concerns shifted, the environmental groups seem to have simply added on various new concerns without re-evaluating old points. So you end up with a lot of the groups now being in a weird state where they're against nuclear, opposed to carbon emissions, and don't actually seem to care much about the actual environment beyond "We have to find a way to keep industrial civilization powered without carbon, and without nuclear." Blowing off mountain tops to extract materials to do this doesn't seem to be a huge concern anymore, and that certainly seems it should fall somewhere under the banner of "environmentalism" - but you mostly hear crickets these days.

If you're looking for something resembling a self consistent environmental group, you can read some of the stuff by the Deep Green Resistance people - their latest, Bright Green Lies, is a decent enough read on their position. That position, simply, is that industrial civilization is incompatible with the planet, and they do a decent job of arguing their position, which is that it doesn't matter how you power an industrial civilization, it does massive and irreparable damage to the planet as a result of the focus on energy and exponential growth. They look at the resource requirements to implement some of the forecast green futures ("We need 3M windmills? Ok, what does that look like in terms of steel, copper, rare earths, and how does that compare with the global production during the timeframe required to build them?") and come to some depressing conclusions. But even if you disagree with them, they show their work decently enough throughout and it's an interesting set of problems to think through.

But in general, you'll find an awful lot of "Climate change is a huge problem; someone else really ought to do something about it!" style thinking in the environmental groups, and I'm pretty comfortable saying that if the last decade hasn't done much useful on this front, continuing the same thing for years to come will accomplish roughly the same "almost nothing."

I'm also not at all sold with the "You can buy your way to green!" solutions that are peddled constantly by those who are interested in ensuring that, no matter what happens, the core of the modern consumerist economy won't be bothered. I'll gesture in the direction of the standard "worried about the climate" somewhat senior tech worker who has a million dollar home, a six figure car, absurdly expensive solar that offsets at least a bit of their power use on their roof, and who feels that they've consumed their way to green, without having really considered any of the resources that actually go into the vehicle, or lower energy/material alternatives to meet their needs. You can directly reduce emissions by simply using less, but this isn't really discussed these days.

I don't see a good path out, sadly. It's very possible we've accelerated growth in a direction that is simply a dead end canyon with no valid paths out that maintain a lot of what we've developed.