I get that elves and dragons are very silly conceptually. But (to take an extreme example), if those elves are involved in a scene of sexual assault and torture, some people are not going to be ok with that. Also they don't have to be "traumatized." Maybe they just find it icky or uninteresting, and now you've lost a new player. Lots of people I introduced to dnd were into the freeform roleplaying aspect, but very not into the default assumption of combat or violence. They weren't traumatized per se, they were just didn't like it (and being the market leader, dnd was their entry point, so they would never move on to other games).As a general rule, people aren't going to be affected that way. If someone is individually traumatized by alignment, elves or dragons, that's the table's responsibility to change.
In terms of the tables responsibility, wotc is very late to the party in providing tools and reconsidering certain elements of the game (like alignment). Personally, I'm skeptical of how genuine they are and if they have the right writers and creators to successfully pull off these changes. From my point of view, wotc, especially in 5e, is too nostalgic and too committed to keeping classic dnd elements.