The problem is not that authoritarian regimes that mark themselves as communist cause a lot of deaths trough Missmanagement and suppression (great famine was mostly Missmanagement). Its how and by whom these numbers are used. When far right politicians call general health programs communism (which its not) and then cite that number (which had already been explained to be much lower), that is weaponizing it in a harmful way to suppress some potentially useful policy. This is what the other commentor was saying with "red scare".
I also think they communism killed x number of people is also bullshit because what do you even call communism? States like Russia under stalin or Mao China were closer to authoritarian regimes than communism as defined by Marx.
Further I think that this number doesn't make much sense at all since it also lacks any context to make it useful.