Most of the time, yes.
This meme is touting blatant lies. Anybody that would post this would receive serious flak and would be totally discredited in the political stream if they couldn't at least provide some sort of reasoning behind the claim. By posting anonymously, they'll never have to. Very cowardly.
There's always exceptions though. If somebody wanted to expose corruption but didn't want to put themselves at risk, I can totally understand their desire to remain anonymous.