This makes sense to me. EA is not really invested in Switch, and FIFA on Switch is a cheap and safe little extra $$$ for them. Why would you spend advertising budget on the Switch version when 99% of your revenue comes from the other platforms? It's a sound business decision.
Sure, EA could have been more invested in Switch, like Bethesda. They could have made a better FIFA game and promoted it as such. That would net them more sales and perhaps also more profit. But they just won't take that risk.