Welcome Lefty! Yeah, for whatever reason, the Phils have played only three games against teams over .500 so far this season, which a statistical outlier. Looks like the next closest are the Dodgers who have played nine. (They've gone 6-3 in those games.) The fact that they've been playing mostly mediocre or bad teams doubtless contributes to their excellent record, but as el-pietro said, wins are wins.
It's interesting that if a team gets lucky and faces a lot of teams who are going through a losing streak, it could end up playing most of its games against teams with losing records.