Political Memes

Here's the thing; if you remove the word "useless" from that statement, I have no issue with it (other than it being factually inaccurate that Greta's parents are "rich").

Yes, it would be the definition of privilege to be well off enough that you can spend your life focused on activism. And that's OK.

Having privilege is not a moral judgment. You're not a bad person because of it. It's just a fact of life. What's important is to understand your privileges. If she was going around moralizing at other people for not spending all their life on activism even though they've got bills to pay and kids to feed, that would be a shitty thing to do. But as the reply in the OP says, recognizing your privileges and using them to help those who are not fortunate in the same ways is exactly the behaviour we want to see more of, from everyone. That can be as simple as being the guy in the meeting who says "Hold on, I really want to hear what Sandra has to say" because you know she's being talked over. It can be a white person filming the cop as they arrest a black kid, because you know that your skin colour affords you a level of safety in that situation. You use the advantages you're given to help others.