They’re probably referring to the fact it was founded by Jack Dorsey, who has since abandoned it because the other people in charge refused to let it be as bat-guano as he wanted.

Ironically, he left Twitter for the same reason. Bluesky was supposed to be his own version, in his image, and yet rational minds prevailed there at pretty much the same time Musk started pushing Twitter in the direction Dorsey had wanted all along.