I just did that (sending a message to a developer), and as posted before I am willing to erase my posts here.
It is not about direct security of bitcoin. It is about boosting the mining algorithm. I don't think it is a direct threat to bitcoin security. Were the first GPU miners a threat to bitcoin security?
As for discussing this openly I prefer to wait for the answer of the developer. I don't want to be accused of spreading FUD or whatever.
Even if there was some way to boost the mining algorithm by some large percentage, at most if would provide a temporary advantage to someone or some group. Difficulty would quickly adjust, and others would discover this "secret." This has been discussed previously too. ;-)
You are correct that the switch from CPU to GPU was not a threat to security. Particularly since GPUs were widely available and could be switched relatively quickly. Satoshi attempted to encourage people (with a "gentleman's agreement") to stick with CPUs for as long as possible to encourage the ease of adoption by more people. It was easier to get mining on a CPU than a GPU. During that time at various points there would be people doing some GPU mining, and eventually everyone had to switch to remain in the mining game, but it didn't impact security significantly.
Hiding what this temporary advantage is - if you think that is what is going on here - is only helping this party who knows of this purported boost to the mining algorithm. I say "purported" because significant claims require significant proof.