That's not quite true. Young was actually OK defensively and while Russell certainly wasn't good, he had begun to learn to use his length to his advantage. I think Lonzo will be worse.
The numbers don't support that, IMO.
Russell: 76th out of 83 point guards in DRPM (61st out of 68 last year)
Young: 70th out of 93 shooting guards (72nd out of 75 last year)
Meanwhile, Larry Nance was 11/81, Deng was 14/70, Brewer was 11/93, and Randle + Mozgov were more in the "ok" range.
Russell, Young, Clarkson and Williams were the 4 worst defenders on the worst defense in the league, and all of it was in line with their whole careers. Ball might fit right in, but being noticeably *worse* is a bold claim considering the baseline.