If I had to guess, and I do, I think it's about the user statistics.
Nintendo STILL won't allow Microsoft or Ubisoft to demand that players create user profiles with their proprietary services, in order to play online.
AND, Nintendo is likely to still offer very little in the way of support framework for online play in the first place.
I'd imagine it to be a "We get it OUR way everywhere else, so if we don't on Switch, we don't play ball" situation for EA.
...Isn't it more logical to assume that their games just don't sell enough on Nintendo consoles to be worth the extra time, effort and money that's required to port them?
No. It is more logical to assume that they have an issue.