Detached condos are typically listed as SFRs. I read somewhere what technically defines a detached condo, but I don’t recall exactly. I know it involves things like zero lot lines, very small or non-existent backyards, shared driveways, things like that.
The practical difference is that they are worth less money.
It makes sense though, that they list as an SFR because the structure does indeed (or is at least intended to) house a single family.