Why are RDMs so scared of SMN being able to heal?

[Kit-Kat]

If the heal is there on behalf of SCH, why not just add it to the SCH spell list? - It's not like ACN can queue as healer anyway.

Because low level content exists, and SCH gets synced down. You want a healer in your run without heals and raise? Healers get their main important tools at low level for a reason. And they can't remove it from SMN's list without hurting SCH, and they can't move it to SCH's job spells instead of base class without screwing SCH over.