We can be fairly sure of that because of the evidence that the capacity for cultural transmission has a genetic basis.
However, memetics originally distinguished itself as a theory of cultural evolution by proposing that bad memes are out there as well - and that we should be cautious in dealing with them.
On type of meme that is often bad are addictive memes. Addictions aren't always negative - but they often are.
There's a recent book that deals with engineering addictive memes - Hooked: A Guide to Building Habit-Forming Products.
Enginnering addiction illustrates the dark side of memetics - rather like propaganda, indoctrination and brainwashing.
While a few work on engineering addiction we must all deal with the consequences of their work. We need strong and selective memetic immune systems. As part of this, resisting memetic addictions is a topic we should all be studying.