Why doesn't Spirit Link count towards healing parses?

It’s such an important part of the resto shaman toolkit, why is it that it isn’t counted towards parses? I get that it isn’t direct healing, but it provides people who need health with health.

Because SLT doesn’t heals.
For example: player X has 500 hp and people Y has 1500 hp. Shaman use SLT. Totem “heal” player X for 500 hp and “damage” player Y for 500 hp(2 player have 1000 hp)

All addons(Recount, Scada, Details) counts only “heal”, and not count “damage”. Logs count all.