How? If the Russians had damaging information on Hillary and want to give it to Trump, how is that at odds with wanting to help Trump?
The damaging information is apparently about Russian collusion with Hillary. The Russians allegedly wanted to help Trump in June 2016, but not before then.
You are not getting my point.
The "substance of the offer" = Hillary is in cahoots with the Russians. In other words, the Russians are helping Hillary, or benefiting from something Hillary did. For example, the Russians are funding the Clinton campaign, or are undermining Bernie, or whatever.
The accusation that is at the heart of the "substance of the offer" to provide information (we don't know what it is or if it even exists, none was ever produced, maybe it's the half million dollar speaking fee or a donation to Clinton Foundation, or allowing the Podestas to participate in a profitable Russian venture) cuts against Hillary.
Of course, making the "substance of the offer" public helps Trump.
The narrative takes on a totally different flavor if the substance of the offer would have been to fund the Trump campaign, or propagandize for Trump. If that was the case, "collusion" is a fair accusation.
My point is that the "trick" you cite, and I agree it will be used, is to isolate the sentence or clause that says "we want to assist your campaign by providing this assistance."
Imagine if there is a parallel offer to Camp Hillary - to produce evidence that Team Trump is buying the services of the GRU to run bots in favor of the Trump campaign. Is Hillary colluding with the Russians if she asks to see the evidence?
Change the nature of the evidence or offer to Camp Hillary, and the entire flavor of the offer can change.
In both cases, the outcome is "to help Hillary."