Memetics consists of terminology and framework for cultural evolution. Cultural evolution covers a lot of hypotheses. For instance there's the hypothesis that the human brain swelled up to accommodate memes or the hypothesis that memes made humans sociable - since they need social contact between their hosts in order for them to reproduce - or they hypothesis that memes were implicated in the high frequency of speciation among our ancestors - just as songbirds speciate frequently. There's quite a lot of associated hypotheses - no doubt some are correct and some are not.

Consider the question: "Where did that viral video come from - why that video and not another video?" - That's the colloquial use of meme, but it's not a very useful question because the answer often "Random chance at the intersection of timing and relevance."

Consider the different question "When did it become unacceptable for males to have intimate friendships with other men?" Looking at the source of that, including with other ideas supported its creation and continuance - is essentially the only useful aspect of analysis of memes.