I mean, it is their by far most succesful franchise so it sort of makes sense that it'd be a gauge og potential success on the platform. Do people think ME Andromeda or Battlefield/front could sell more on the Switch than Fifa?

The fact they are using FIFA as a measuring stick is not the problem. The fact they are bacically coercing the Switch userbase into buying it (a lesser version than the PS4/XBOne equivalent) or they might consider not bringing anyting to the Switch anymore, is. You do not threaten your potential playerbase like that.

I think you are reading a lot into his words...

Here's what the dude said:

 “I’ve made people repeatedly, publicly aware that I’m a gigantic Nintendo fanboy. Nintendo was what got me into this industry in the first place. I take my Switch with me everywhere.
What I will say is, we will appear on any platform where there are consumers, and players. We believe that we want to be a part of the Switch, and help Nintendo grow that installed base; that’s why you’ll see FIFA, which by the way is really good this year. It’s a full-fledged FIFA game, for the first time to be honest, on a portable device.
But at the same time we have to look at it from a resource standpoint and, at some point, the numbers become a factor. So for us it’s about supporting the platform, building technology for the platform, testing it out with big things like FIFA – and maybe a couple of others, we’ll see – and if they go well, I see no reason why we shouldn’t have as much of our portfolio on that platform as possible. I hope we get there, that would be my personal ambition.”

He's being honest. If the games they put on the platform first see success, then more will come. Do you think they'd just pledge unconditional max support, ala Ubisoft's "unprecedented partnership"? Besides, every game they might put on the Switch will be a "lesser version than the PS4/XBO equivalent", with the exception of being portable (which Fifa also is). If portability isn't enough to convince people to buy Fifa for the Switch instead of on PS4/XBO, why would it be enough to convince people of buying other EA games on the Switch instead of on PS4/XBO?

They're a business. They can't just say "Oh yeah, we'll support the Switch, doesn't matter if the sales actually justify that support."