Which is odd. Maybe they anticipate something with Tesla's dropping in value that the other entities don't know about. This is pure speculation, but why on Earth would they price themselves out of getting someone's trade for a perfectly great opporutnity to resell one of their own cars, but they'll take in other brands. Logic follows that if you're asking about trading your Tesla, you DONT plan on keeping it anyway, it makes zero sense why they wouldn't want to capitalize on the opportunity by offering a more competitive trade value for customers. That's why I think they know something others do not regarding short term future value. That's what logic would tell us anyway.
Don't forget that Tesla no longer runs a certified pre-owned car program. So they have no interest in doing much with used cars like a typical dealer would.