It’s about balancing the bets. The Dodgers probably see more betting action than any other team because of their city, star power, and overall popularity. That will push more money towards their side even when they might be actual underdogs.
I’d be surprised if they aren’t a favorite for the first 50 games. Depending on how they play, injuries, and other factors, the streak could end at some point. But I bet it goes for a while regardless of the opponent.