I see now, that makes sense why you are building the image since it was set up that way. I don’t know why projects set up the compose file to build the image when they already have a publicly available image to use; it just creates unnecessary friction for people who just want to test out the software. Anyway, using that image should work for you, but feel free to ask if you run into any issues.
It’s because the original image macro that this is based on was about piracy, saying something along the lines of “I bring a certain ‘just torrent it’ vibe to the conversion that the riaa just doesn’t like.”
Their reuse of the macro is indirectly an answer or a continuation of it that can be seen as acknowledging the original message.