Friends don't sue each other, right?

So it would seem to be a bad idea for animal rights groups to sue the EPA because the EPA is going to not do something they never started doing anyway. Activists need the EPA to enforce their goals, they have no authority without the EPA or various other federal laws and bodies to oversee laws that highly-paid lobbyists convince lawmakers to pass.

While it might lead to hurt feelings if you and I sued each other, for activist groups and the government, it is not only smart strategy, they sometimes plan it together in advance. Why? Once a lawsuit is filed, the EPA can 'settle' - since the EPA is an appointed body outside lawmakers and the public, as long as the White House does not object to their settlement, it will be fine.

A common technique of activists and people who generally distrust science and want to undermine it is to clog up the discourse with sophistry, like "it depends on how you define X", or they claim that their personal belief means science is not science, but rather morality. 

The administration can turn a blind eye to enforcing federal laws when it comes to marijuana farming but they won't have a choice when it comes to pollution - because they will get sued into taking action.