With Apophatic theology, we attempt to describe something in negative terms, which is popular in explaining God through what he is not, like he is not limited, bodily, ect.
So with Universal Salvation, there is an apophatic quality in that it tells us what our ultimate destiny is not. As in its not to cease to exist(materialism), to be endlessly reborn(Reincarnation), eternal darkness in some gloomy underworld, or an eternal divide between good and bad people, or the saved and damned.
At best, what we can say that with salvation that it is absolute union with God. However, we really can not really explain what unity with God is like. Its not something that can be explained, like in popular and ancient Pagan beliefs of a continuation of earthly life, like the happy hunting grounds, land of clouds and harps, or some kingdom in the stars. Nor a gnostic view of release from ordinary existence into some realm of pure essence, free from time, space, matter, and feelings.
I wonder if we make the doctrine of UR too complicated sometimes. Many people believe in the doctrine for many reasons, both valid and invalid, such valid ones as hope of heaven for themselves, hope of heaven for their family, freedom from the fear of hell, or invalid reasons like a license to sin, spiritual sloth, or just to go against the grain. Then there are reasons centered on theological philosophy and bible centered logic. Like the most popular is that Universalism is true because God is all Good and all powerful. So eternal damnation would be utterly illogical. Or counting up Bible verses Universal Salvation vs. Infernalism vs. Annihilation, and compare and contrast, along with other logical formula, and whether the overall message of the scriptures resembles UR or ET or Annihilation. Then there are Moralistic reasons for believing in Universal Salvation, like the idea that a good person includes everyone, that good people dont torture people endlessly, and the penalty does not fit the crime. Then it goes deeper, with whether a good God should allow powerful forces(Demons, genetics, culture, and society) to eternally corrupt people, whether someone should be allowed to make an eternal decision with such little information, or if a Good God would create a being that he knew would choose an existence bound to sin.
Plus, we have other habits of trying to give tangible image of universal Salvation, like a Socialist Paradise where all all social classes are abolished, and a benevolent government controls everything, or a brave new world order where technology has made people into happy slaves, or total anarchy without any form of authority to punish people for disobeying rules(This would only work out if one saw authority as the root of all evil).
The same could be said for Infernalism or annihilation. Annihilation could be seen as Utilitarian, in killing some off to save a larger number(larger hope), or elitist in killing off most to protect the privilege of the elites. Where Infernalism could be seen as fascist in using cruel punishments for offending the leaders majesty. Or could be seen as elitist in corporatist where things only work out for a select few, and the rest are fated for turmoil.
Then there is the other challenge to the moralism of UR vs Infernalism, in whether with an universalist perspective is God bound to laws similar to the constitution, Designed for people, or is the law relative to what God says? Whether its to the benefit of the people.
So does the abuse of the doctrine, and the tendency to complicate it make it invalid? I would say no. Now you can say the same about Infernalism. Just because it makes God look fascist, irresponsible, psychopathic, draconian, or pharisaical. As far as I can understand, the only way that Infernalism can be justified is if someone with absolute full knowledge knew how horrible sin was, and how it would put them in a state of destruction, and still chose it. Either way, with Infernalism, its clear cut, your doomed to an evil existence. Then, this begs the question on how to avoid this fate, hence a way of saying what kind of people God likes, hence defining God.