I think too often the catholic idea of the moral "middle ground" is interpreted erroneously. The true "middle ground" has to do with the old saying that "virtue lies in the middle" BUT this doesn't apply in all cases. Virtue, in opposition to the world is VERY EXTREME. The saints were VERY EXTREME. For some virtues there is NO extreme (faith, hope charity). For the rest, they must be tempered (i.e. blind obedience is wrong). Being in the middle is usually not good.
In the 70s the extreme wrong was the novus ordo; the right view was traditionalism, which rejected the novus ordo. The middle was the sspx which never rejected the novus ordo wholeheartedly.
Nowadays, the sspx is still in the middle, but they're way closer to the left, having become a quasi-indult, which is the logical conclusion to their 70s lukewarm stance on the new mass. The middle is not where you want to be. "Be ye hot or cold, the lukewarm I will vomit from my mouth."