Yeah makes sense. Also just looking at the splits leaderboards, the top 4 teams vs. LHP in wRC+ are all in the AL (NYY, HOU, DET, BOS).
The Dodgers are at 115, the Cubs are 2nd at 112 (surprise), and the Phillies are at 106. Every other NL team is under 100. Obviously Philly is above average but the only dangerous NL team IMO would be the Dodgers and they are dangerous regardless (119 wRC+ vs. RHP)
Edit: Should also mention, here are a few other NL Contenders vs. LHP:
Brewers - 98
Mets - 95
Padres - 91
Cardinals - 88
Reds - 79
Giants - 76
So if anything it may be an advantage to have 3 lefties topping the rotation this year.