That is the traditional definition of the 0 hour of RA. If we kept with that strict definition then the position of 0 hour will change every year as the sun does move a bit every year. This would make it impossible to locate items (Declination also moves around) to the required accuracy. As a result of this realization, a particular point in the sky has been defined as being 0 hour, 0 dec. As long as you think that the position of anything is dependent upon what some repetitive thing (like the annual crossing of the equinox) then you will be confused as you are trying to redefine something that can only be defined once. It would be like saying that next year is 1A.D. because it is the next year.