Memes can refer to a bunch of things, but in this case I'm referring to memes that mock the enemy's agendas/narratives.

Here is one example:

I sexually identify as an attack helicopter

I sexually Identify as an Attack Helicopter. Ever since I was a boy I dreamed of soaring over the oilfields dropping hot sticky loads on disgusting foreigners. People say to me that a person being a helicopter is Impossible and I’m fucking retarded but I don’t care, I’m beautiful. I’m having a plastic surgeon install rotary blades, 30 mm cannons and AMG-114 Hellfire missiles on my body. From now on I want you guys to call me “Apache” and respect my right to kill from above and kill needlessly. If you can’t accept me you’re a heliphobe and need to check your vehicle privilege. Thank you for being so understanding.

He's mocking "gender fluidity". The completely false narrative that someone can just change their gender to whatever they want at any point in time, and others are supposed to feed this mental illness, or you're a transphobe.

Memes can be an extremely successful means of attack against the enemies agenda, because it often encompasses humor into the equation. And younger people can understand it.

The alt-right for example, has used memes to attack the enemy's agenda successfully.