obviously it has bad rings if oil is coming out of the head gasket.
Not necessarily.
All head gaskets leak to some extent...oil burning or not.
It can also be argued that all engines burn oil. Oil levels normally drop and cannot be attributed to anything affiliated to evaporation. So where does it go? Out the the exhaust port or breather (blow-by).
The line has to be drawn as to what is (perceived to be) too much leaking past rings or head gasket.
There is no such thing, ultimately, as a "perfect" seal...be it gasket or rings.
A certain amount of seepage is quite normal and expected.
Rebuild is not necessary unless it is determined that there is a significant loss of power.
Rebuild is a last resort.
I might also add that lighter oils (especially multi-grades) will leak/burn more quickly as evidenced by the brownish tinge on cylinder walls of older engines.