That quote was touting the features, not saying that the National Dex was cut for higher quality animations.

Immediately after that he says they had already been discussing limiting the number of pokemon, and that the main reason is they cut the National Dex because they felt that it would allow the new pokemon to shine and improve balance.

We knew at some point we weren't going to be able to indefinitely keep supporting all of the Pokemon, and we just found that Sword and Shield would probably be a good point to go back and reevaluate what would be the best selection of Pokemon that appeal to the widest audience while keeping into consideration the balance of the battle system. It isn't just going to be all-new Pokemon in the Galar region Pokedex; there's still going to be a lot of favorites that fans will be able to bring over that they've adventured with previously. But yeah, it was pretty much just balancing and getting this optimal selection of Pokemon for the adventure we wanted to provide.

You don't have to like the decision, but stop acting like you were lied to because you didn't read it closely.