Do groups that subscribe to “environmentalism” not exist? If I looked up something called the “Sierra club” what would it say?

It would be an environmental group, with members who pay dues, attend organized meetings, put Sierra Club branded calendars up on their walls, and so on. The Sierra Club has organizing documents, officers in charge of various functions, and written communications outlining strategies, paid employees, etc.

“Antifa” has none of those things, just as “environmentalism” has none of those things. Neither does “Christian” or “liberal” or “black” or “short” or “vegan”. There may be organized groups within those broad categories , but they are not organized in any meaningful way, just as “antifa” is not.

And does that mean that “environmentalists” can’t possible share the same playbook?”

Of course they can, just as vegans and vegetarians share much of the same playbook. But there is no group of “vegans” you can point to, although the Farm Animal Rights Movement certainly embraces the precepts of veganism. You might be able to indict the officers of the Farm Animal Rights Movement, but you certainly couldn’t indict the members of “vegan” because there are no “members”, see?