I think it is quite reasonable to argue that all memes have a conceptual part, even a behavioural meme that is learned by imitation. So I suppose it is ok to think of a meme as a concept that is passed on from person to person.
I think justice is a significant meme as it has existed for a long time and seems to exist in all civilisations.
I use the term 'conceptual abstraction' because physical abstractions exist, such as a diagram. A diagram of a desk is not a desk; it is a physical abstraction of it. It represents some characteristic features of a desk which may be used to identify objects as desks or create objects that could be identified as desks. Nonetheless, it is likely that for every physical abstraction there exists a conceptual abstraction if one needs to recall it and manipulate it in the mind.
I must declare that I am not an expert on memes. If we all had to be experts in everything we discussed we would all have few discussions. If someone reading this is an expert on memes, then I would welcome a more thorough explanation. I believe the important aspect of the meme is the sense of it perpetuating by its own merits through civilisation. Not all concepts do perpetuate due to their own merits, so they are either not memes or at best are unsuccessful memes. A concept that having been created is never passed on is still a concept, but not a meme.
It should be becoming patently obvious to you that the sort of things the word 'meme' is supposed to represent, simply loose their meaning and significance when you use meme to describe them.
Meme says nothing about the things it describes.
Wearing your baseball cap on backwards is a meme, but so is that cap itself. Justice is a meme, and so are all the practices it encompasses, including the death penalty, and imprisonment.
Injustice is a meme too. Hate is a meme, and so is love. Pick an idea, a cultural practice, and you have a meme.
What is the use in calling everything a meme?
It seems to me to be the worse thing you can do, if you want to understand a thing is to reduce it to a meme.