Not saying are or aren't, but what's your reasoning?
He probably has his own analysis, but my reasoning is as follows:
1. Nets are probably the best matchup for Lopez in the East, they have Jordan, a non-perimeter defending, non floor-spacing big at C. He will either have come out on Lopez, leaving Giannis to feast on their poor perimeter D, or stay inside to try and help.
2. Our Big 3 matchup well defensively against theirs. Jrue can guard either Irving or Harden effectively (I would actually guess they throw him on Harden) with Giannis being able to matchup on Durant. Not sure how DDV would fare on Irving or Harden but he's no slouch defensively. Middleton can guard Harris or Green effectively.
3. Nets have nobody that can reasonably be expected to check Giannis at all, nor do the Nets have great personnel to build a "wall" like Toronto (Kawhi, Gasol, Siakam, OG) and Miami (Butler, Crowder, Bam). Harden/Irving/Harris are all very poor defensively, and if they throw Durant on him Giannis can abuse him inside.
4. Assuming they put Durant on Giannis, Middleton will absolutely destroy whoever they put on him.
5. Neither of their guards can stop Jrue from getting to the rim.
Essentially, the summary from above is that the Bucks are a much better defensive starting five than Brooklyn. Very good likelihood that Brooklyn ends up being the best 3 point shooting team in the NBA, but Bucks appear they will also be top 5. The difference is that they are well rounded on the other end, and Brooklyn is not.