I sometimes steal memes from one group and share them with another without liking or crediting the original meme
Why do you like to share memes to another group?
It's more interesting to look at what people have to say about the original meme
While it is good to share with others what you think is funny, it is not good to not give credit to the person who created it. It is not fair after all the hard work they did and it doesn't take much to give credit.
By sharing what is funny and not what is not, I'm helping out the original poster.
I don't see how this helps the original poster, if no one even knows they made it. It's easy and kind to share a link to the original meme. You can still enjoy the process of sharing it with others.