I don’t know what you mean by right or wrong but as far as good or bad, yes, it was BAD. The holocaust was VERY BAD. The Churban was VERY BAD. What does the fact that it had to happen have to do with it being bad?
I think it’s called getting carried away. When you are discussing the event and what it did to people that is not the time to talk about how it had to happen. It is important to realize that nothing happens without Hashem’s permission, but don’t blur the lines. Hashem Himself cried by the Churban, and no doubt, by the holocaust.
Whatever the Pshat is for the Onash (the Rishonim discuss this) of the perpetrators, we see in the Psukim that Hashem’s attitude concerning the ones carrying out what He promises, is as if they went ahead and did it on their own.
There are many people who readily tell people suffering that it is all Bashert, while usually forgetting that fact when it has to do with themselves. Actually, it is not always the right thing to tell someone. It can be taken like invalidating their feeling. The correct attitude is that what was wrong was wrong but don’t think, had he not done that I would have had…
It pays to learn more about this topic.