So to the best of my understanding, the Eastern Orthodox Churches and SSPX are in the same legal standing-- valid, but illicit.So why is it the case that practical Catholics can receive the Blessed Host at a SSPX Parish and not at an Orthodox Parish?
They do not have the same legal standing.
Eastern Orthodox churches are “Churches”. They have all valid sacraments. They are fully in union with an ancient, apostolic Church, united under valid ordinaries, both clergy and lay members. They just are not in union with Rome. The Catholic Church has no jurisdiction over them in terms of sacraments, etc. Besides dioceses, they also have their own parishes, with pastors.
The SSPX is not a “Church”. They do not have lay members. They “recognize” the validity of the ordained bishops of the Catholic (and probably Orthodox) Church, but are not themselves under any ordinaries. In other words they regard Bishop X as **an **ordinary, but not
their ordinary, though they may choose to agree with him on some things.
They have validly ordained clergy, and under certain circumstances, some sacraments there are valid. All SSPX members - that is, clergy and religious, as well as any non-member but personally loyal or attached laity, are theoretically under their local RC ordinary. Depending on the individual, and depending on the bishop, they may regard their local ordinary as more or less agreeable or relevant ** for them**; but the priests don’t necessarily accept the
authority of the RC ordinary downtown, over them. Laity loyal to SSPX may choose to belong also to a Catholic parish. Then they would be under a pastor. The SSPX does not have pastors, as such, since there is no ordinary to appoint them. Chapels do have priests to offer spiritual guidance.
The SSPX does not have parishes, they have chapels. They do not have dioceses; again, it is a religious order. The SSPX does have discussions at times with the Vatican, but as a Catholic group, not ecumenical discussion. It is not “under” the Vatican office that oversees religious orders, though the SSPX may choose to follow RC canon law, in some matters. The pope can grant permission for SSPX priests - Catholic clergy - to hear confessions. He has no relationship to EO clergy.