I don't think it's impossible for the Raptors to beat Golden State.
Durant is hurt and may not play. I also think Golden State could have a bit of Milwaukee in them, meaning: Milwaukee blew through the first two rounds and then went up early on the Raptors, only to see a team that had battled against the 76ers turn the tables on them. It's like they relaxed after the first two games and were out.
Also. and this point is interesting, Golden State feels like a team of stars looking for a reason to implode. Think about the Kobe/Shaq Lakers. They were amazing, but eventually, despite all their success, they blew up and separated.
If the Raptors can get in their heads, who knows what can happen.