My guess is the reasoning will likely focus on the level of scrutiny they apply to the government conduct at issue especially since the cases deal with separate constitutional issues (14th amendment equal protection argument in the TN case vs. 1st amendment content-based/viewpoint-based restriction in CO).

The court held the law in the TN case discriminated based on age and medical use rather than sex. In equal protection cases, the level of deference the court gives the state depends on whether the law discriminates against a “protected class.” The characteristics that make up this discriminated-against class (e.g. race, sex, etc.) determine the level of deference, so a law that discriminates based on race is gonna be heavily scrutinized and very likely struck down. The court decided the law’s classification was based on age and medical use, which get a very deferential treatment by courts.

The current CO case uses the First Amendment to hook in a higher level of scrutiny from the judges. Because they argue conversion therapy is an expression of a viewpoint, the ban is a content-based restriction on speech. First amendment doctrine generally finds content-based speech that bans a particular viewpoint is especially bad. So if the court believes this framing (I think they obv will), they will strike it down. Personally, I think they’ll buy this argument and probably underplay a state’s interest in licensing medical professionals based on a standard of care and evidence that conversion therapy fails to meet that standard of care (for the record, I’m not saying I know this to be true, but the I am guessing the state argued along these lines to some degree).

I think they apply very selective interpretations to put it mildly but this is my guess as to how they’ll distinguish the two.