I get all that, and don't disagree with batting Olson 2nd. That said, with the three batter rule, managers often make the pitching decision at the beginning of the inning. Thus if you bring in a RHP to face Albies and/or Riley, he has to face Olson. If you bring in a LHP knowing Olson is coming up either 2nd or 3rd, he has to face Albies and/or Riley first.
OTOH, if Olson (batting 4th) is leading off the inning and you bring in a lefty, he then has to face Ozuna, TDA, and/or Arcia.
Bottom line, Olson (.790 OPS) is still a decent hitter vs LHP, and as long as he is three spots removed from Harris, it's pretty much an academic discussion. If a manager brings a lefty to face Olson (whether or not he is leading off the inning) , he has to face two RHB (either Albies and Riley, or Ozuna and TDA/Arica) who have a platoon advantage, and in at least one case (Albies) has a large platoon advantage. Everybody talks about "lineup protection" in the context of who follows a hitter, but, especially with the three batter rule) it can also be viewed in the context of who precedes a hitter.