By exploring what could happen if Wanda were allowed her freedom, WandaVision has proven Tony Stark’s point about her being a threat. In Captain America: Civil War, Stark recognizes that her accidental murder of hundreds of civilians might only be the start of what her powers could lead to. He was right to be concerned and the Westview Incident proves it.
In the wake of the Lagos incident, Wanda was placed under house arrest without realizing as much. It falls to Vision to reveal to her that he is effectively her prison officer, making sure that she remains in her quarters under his former master’s instructions. While he attempts to raise her spirits and allay her concerns that everyone is scared of her by saying the response is involuntary, Vision is still enacting the Sokovia Accords on the object of his affection.
The Civil War moment is played as a betrayal by Vizh who admitted that her being kept at home is “a question of safety” and not Wanda’s. The synthezoid confirmed further that “Mr. Stark would like to avoid the possibility of another public incident. Until the Accords are a more secured foundation.” It may seem cruel, considering Wanda has just candidly spoken not only about hating the fact that others fear or hate her but that she is still herself despite her powers, but Wanda’s loss of control in WandaVision shows Tony’s fears were right. Even if they were mangled by his own heightened anxiety.
In the same conversation with Wanda, Vision discusses control and the enigma of the Mind Stone and its impact on him. He expresses a desire to come to learn and control the Stone, drawing an unspoken parallel to Wanda’s own condition in the wake of the Lagos disaster. She doesn’t know the limits of what she’s capable of nor how to control her powers, just like Vision and the conversation is designed to be an appeal from Vision for Wanda to listen to the sense of Stark’s urge for careful consideration. Tony was painted as the inhuman monster in that dynamic, but his feelings were built on his own experience and the fear of other Avengers repeating his loss of control that put the Earth in peril during Age of Ultron.
Tony’s desire for accountability and control from the Accords was also motivated by his desire to keep his super-family together in the face of what could be an unthinkable alternative. And WandaVision has proven both that Wanda is a huge threat when not in control – because she was always designed to be a weapon of someone else’s use – but also when she’s isolated. It is ultimately both of those that Agatha Harkness preys upon in order to target and potentially weaponize Wanda. So while Tony may have gone slightly the wrong way about it – as ever – he wasn’t entirely wrong.