Meaning of はじめからわかってるだろ


Looking for some helping understanding the end of the below (more in context,
rather than literally what is said). I can see how it was translated but I am
unsure what is correct. To provide some context, the protagonist has been
cross-dressing (unwillingly) when his club were carrying out certain
activities and he has acquired quite a fan base with very few people outside
his club knowing this it is him. Now in return for allowing their club to keep
their club room the chairman wants to have a personal photo session (個人撮影会).

> みんなが俺を見ている。
>
> というか、視線で恫喝している。
>
> まさか断らねえよな、と言っている。
>
> 「で、でもほら……今日、汗かいちゃったし、恥ずかしいな」
>
> 「むしろ喜ばれるかと」
>
> 「事務所通してもらわないと」
>
> 「いいよー、行っといでー」
>
> 「いや、つーか、脱いだら男だってバレるし」
>
> 「そこがいいんだってさ」
>
> 「その委員長、終わってるじゃん」
>
> 「 **はじめからわかってるだろ** 」
>
> 総括すると、どうやら俺は売られたらしい。

The bold line was translated as "He probably knew from the beginning." (i.e.
the chairman knew that it was him from the beginning) however I am not quite
sure this is the correct translation of what was said. I would have expected
this to be phrased differently if she was saying that e.g. a sentence using
バレている, 気づいている etc. To me I interpreted it as a response to the previous
comment. Could anyone help clarify the correct understanding?




I think you are correct. It's a response to the previous comment, and the
translation in this context is probably more like this:

> そこがいいんだってさ。  
>  He said that (=脱いだら男) is exactly what he wants.
>
> その委員長、[終わってる](https://japanese.stackexchange.com/q/62169/5010)じゃん。  
>  That chairman is hopeless.
>
> はじめからわかってるだろ。  
>  **We** all knew that (=the chairman is hopeless) from the beginning, don't
> we?

そこ **が** いいんだ **って** さ (with exhaustive-listing-が and quotative って) means this
委員長 is fully aware that he will take photos of a 女装男子.




I think you are correct. It's a response to the previous comment, and the
translation in this context is probably more like this:

> そこがいいんだってさ。  
>  He said that (=脱いだら男) is exactly what he wants.
>
> その委員長、[終わってる](https://japanese.stackexchange.com/q/62169/5010)じゃん。  
>  That chairman is hopeless.
>
> はじめからわかってるだろ。  
>  **We** all knew that (=the chairman is hopeless) from the beginning, don't
> we?

そこ **が** いいんだ **って** さ (with exhaustive-listing-が and quotative って) means this
委員長 is fully aware that he will take photos of a 女装男子.

