More PS4 players have those titles. Did they buy a PS4 specifically for those though when they could get them elsewhere? For example if there's 5 COD players. They all want COD. One wants COD and was an MGS fan. So he gets PS4 for COD and DS. Another gets it for COD and Ratchet and Clank. Another gets it for COD and TLOU. Another gets it because COD and Horizon looks cool. The fifth gets the Xbox because he loves Halo and COD. PS4 exclusives sold those 4/5 gamers even though each one is only getting 1/5 of the COD sales.
I think you underestimate the number of people that buy a console just for FIFA and/or COD. Plus who actually plays (or wants to play) FIFA on PC? And Xbox is barely even a thing in Europe so I'm pretty sure there's a whole load of people who bought a PS4 specifically for FIFA.
Bet Shiken that COD would outsell Battlefield in 2018. http://gamrconnect.vgchartz.com/post.php?id=8749702