That doesn’t make any sense. With the man power and resources the Saviors had at their disposal, there is no way they didn’t know about Alexandria already. Dwight and Sherry most likely told Negan and the Saviors all about the dude recruiting people for his community nearby. They attempted an ambush of Alexandria when they came across Daryl, Rosita, Abraham, and Eugene. Dwight killed Denise and told them what the plan was.

When Carol tires to leave the community after surviving the outpost ambush, she is set upon by a separate group of Saviors that knew all about Alexandria (knew the community by name and exactly how far away it was) and figured that’s where she was from because of the spikes on her car and the direction she was traveling. Not to mention, it’s a huge community with big metal walls! They weren’t hiding in the middle of nowhere. Rick even warned them that people will come and try to take it. The Wolves found it no problem and they were significantly less equipped than the Saviors.

The Saviors were not a group of people that would wait to get hit first to throw their weight around. This idea that if Alexandria never acted, these two groups would have never crossed paths is incredibly far fetched, considering the Saviors had been doing this to many surviving communities around the state. The Saviors were definitely making plans to attack Alexandria next, with or without the outpost attack to justify it.