It's not that bad if you live in a country with little to no footballing presence, like Bangladesh or India. Those people deserve to enjoy the World Cup cheering for a team too. And sometimes it's justifiable even if you comes from a country with a strong footballing culture.

I'm Brazilian and I can say that I actively support the France NT. I have family in France and when I lived in Paris I used to attend matches at Stade de France fairly often. I actually attended more France games at the stadium than Brazil games at this point. It's also nice watching the Euros cheering for a team.

Of course I love my national team above any other team, but when my own national isn't involved I don't see why it's considered "toxic" to root for another team.