Being nice because they are new, as opposed to putting a reposter on blast and watching them get trolled by the Imgflip community.
It's a "Do unto others" sort of thing. You wouldn't want someone else taking credit for your clever and original memes, so if you're going to repost (which is even mentioned in the rules when you submit a meme), at least say so.
But, whatever, do what you want... Don't whine if you repost and everyone trolls you about it.
