I imagine some of the board voted that way because it is easier to explain why Boston is .500 and the 10th seed, rather than what to come to the conclusion that Boston just isn't very good.
If things broke right, I think there are only 5 teams that could reasonably win the title this year: Milwaukee, Brooklyn, Golden State, Phoenix, and the Lakers (I've said all year I thought the Bucks would repeat and that still holds firm). The Lakers are obviously a mess right now, but they still have 2 top 10 players in the sport (or at least what should be two top 10 players in the sport) and that generally matters in the post-season especially when one of them is the greatest player in NBA history.
The next tier is basically Utah and Philadelphia (and if they get the Simmons figured out, they could jump up and make it 6 teams because Embiid has the potential to take over games). Then I'd put Miami all alone (they have a top 15 guy and very solid depth around him). After that I'd trust the reigning MVP's team (Denver) or a guy many believe will retire as one of the greatest players ever (i.e. Luka and Dallas) over teams like the Bulls, Wizards, and even the Celtics (who are a flawed injury riddled mess right now). Given the Hawks' run last year, I have some faith in them, but I don't think they are really any better than Denver or Dallas (maybe a bit more depth, but not as good a player at the top). And I know MPJ isn't coming back and Murray might not either, but even without them they have the reigning MVP in his prime, solid role players like Gordon, Barton, Morris, Green. Unless you have no faith in Jokic, I don't see how you could reasonably think that team is worse than the Wizards (as an example).
The criticism of the Grizzlies is fair (i.e. young and inconsistent), but the Grizzlies have had far more success (i.e. making the playoffs last year) than teams like the Cavs and Hornets, where the young and inconsistent would also absolutely apply. The benefit of the doubt is only given to the teams in the East and not the teams in the West, which doesn't make a lot of sense to me. I'd trust Paul George and the Clippers (even without Leonard) over those teams because Paul George has been there and done that and is a top 15 player in the sport in his prime. They won't win a title without Leonard, but Paul George led a similar team to several playoff victories, including clinching the Jazz series and then 2 against the Suns, without Leonard. I can't see the Cavs, Wizards, Knicks, or Hornets doing something like that.
The East has a lot of decent regular season teams (the Bulls for example i.e. a team with a lot of solid role player type players), but they don't have a lot of teams I'd trust in the playoffs because they don't have the top tier talent that by and large lead teams to playoff success. Top end talent matters and it matters a lot in the playoffs. It always has and it always will. That is why it is actually important to note where the best players in the world are, because their teams are going to be the ones that are winning games when it matters.