I mean, in an abstract sense your concern is valid, but, at least how I see this case, this racist dogwhistle is very fragile, in order to stay discreet, and the meme is very low-stake to use.

The "battle arena" is also the chaotic "meme market", where there is much less top-down control too, and individual idea virality reigns king. That is to say, as long as you explain your idea well, as long as your meme "hits a nerve", it will spread either way.

To be exact about what I think, I think we should do both: 1. Use the meme as a meme, because it's fun and dilutes the use of the dogwhistle, and 2. Explain the dogwhistle when we get the chance, without telling people to not use the meme. The explanation helps expose the racists, the meme delivers the antidote.