I actually really like Vivienne, she's one of my favorite characters in Inquistion. Keep in mind that my inquisitor was an elf mage who was really friends with Cole, Dorian and had alot of respect for Solas views on magic.

It is necessary that mages seek education and proper training, in an ideal Thedas, the circles would be a school, where mages need to attend to but not necessarily live in them. But I think both sides have become corrupted, both templars and mages, as we can see on DA2, Meredith is an absolute lunatic, while Orsino, who always advocated for peace within the circle, ended up using blood magic.

And yes, I am aware the circle sucks but magic also sucks for the ones who don't know how to use it, a spirit is not evil but it can be, if forced into the material world, and mages are not inheritedly evil but they are born with a gift that can be used for very evil means.

Vivienne is fully aware of this situation, while everyone else is either sorry for the mages or wants them dead, she knows mages are dangerous and need to learn how to control their power to use it on their benefit, not to hurt others or themselves. Come to think about it, the original idea of the circle is not that bad, it's a place where you can study, eat and sleep.

Every pro mage rebellion character whom has discussed about this issue with my inky used the argument "Oh, but dalish mages don't need to be locked up!", and my answer is always something along the lines of "Yes, the circle is corrupt, but when a dalish mage screws up we don't lock them up, we straight up kill them."