And what if someone sells them into slavery afterward? Tevinter is honest that might makes right, so if a Magister decides to gruesomely execute their elves, they can. An "honest" horrible place is still much worse to me than a slightly less honest place that's merely bad. And Tevinter is much more horrible than any other country. I mean Loghain selling elves into slavery was still a scandal in Ferelden. In Tevinter something like that would be normal. Not only that, is there any reason to think that Tevinter elves don't face the same prejudice when leaving the alienage? The highest non mage class of people in the Imperium are the soporati, and World of Thedas says they are "overwhelmingly human."
1) No, it wasn't. One nobles voices disapproval for the notion but no one really cared. In fact I'm pretty sure it was one of the charges that shifted the landsmeet the least, if not at all, against Loghain.
2) "Overwhelmingly human" considering that dwarves are never considered to be citizens, that means there are at least some elves are members of the soporati class. As opposed to say in 'nice' countries, where all elves are either alienage wage slaves [which is actually worse than being a slave, since people at least have an actual incentive to look after their own property, even if that property is other people] or members of the circle/apostates/dalish.
Does it say anywhere that Tevinter's elves chose to stay after Andraste's Exalted March? Because I've never seen any reason to think that they weren't just prevented from leaving.
IIRC, it was part of one of the Tevinter Elven slave's account on the long walk to the Dales, where they were given a choice to stay or leave and they chose to leave despite the hardships and being treated relatively well by their master.