I don’t think anyone is downvoting you for saying Python is slow. You were downvoted because it’s not a substantive comment. You’re replying to a title instead

I don’t think anyone is downvoting you for saying Python is slow. You were downvoted because it’s not a substantive comment. You’re replying to a title instead of engaging with the contents of the article, and even then it adds nothing to the discussion since “that slow” isn’t well defined, anyone could say “yup” or “nope” to any imagined value of “that”.