Roughly 11:50 into that podcast, which is called Pull Up With CJ McCollum, 2016's Most Improved Player called the Cavaliers "one of the worst defensive teams I've ever played against."
Frankly, I think most people (Cavs fans included) would be hard pressed to disagree with that. In fact, the top comment was from a Cavs fan who wrote "Is this a surprising thing to say?"
Nevertheless, McCollum stated that he thinks Cleveland's deficiencies come from the team's high roster turnover.
"Cleveland is one of the worst defensive teams I’ve ever played against, honestly," McCollum said when speaking on the Eastern Conference Finals, as transcribed by Larry Brown Sports. "I think it’s just the spacing, they have a lot of different players on their roster throughout the season, so terminology’s not the same, the continuity isn’t always there."
McCollum continued: "Think about how many players they’ve had on their roster the last three or four years [...] They’re literally in and out, new guys every year. So it’s hard to be on a string and be united as one when you have all that uncertainty: ‘Hey, if things don’t go well, I might get shipped out.’ So I think that’s one of the reasons why their defense has been up and down. But then when it’s time to lock in and focus on one team, they’re a lot better."
The Cavs ended the 2017-18 campaign ranked 29th in the league in defensive rating (ahead of the team with the worst fucking record in the NBA, the Phoenix Suns). If there's a silver lining for Cavs fans crossing their fingers to beat Boston and then maybe win a single game against Golden State, McCollum did note that the reigning East champs are able to lock down on a team when it's time to focus, which one would think serves well in the postseason.
The Cavs are currently tied 2-2 with the Celtics. Catch Game 5 Wednesday night if you feel like it.