Well that is true, but this is part of the game. Faster mining software often helps the early adopters (because they can mine with low diff and high hashrate). Later on when everyone is mining with high speed we will be back to normal profitability. But for MinexCoin it is better this way. Why?
Well we see now what hashrate is possible. Assume that anyone that wants to corrupt the coin is able to write a mining software much faster then the existing ones. If then the hashrate of the network is low because the algorithm is not that optimized or because only Linux miners are mining then it is easy to collect enough hashrate to try an 51% attack on the coin.
Now the hashrate of MinexCoin will increase and the software will work (hopefully stable in future) on multiple platforms. Then is also gets harder fining a better implementation or running an attack. Overall this strength the coin. Now lets hope no one does a ASIC for Minex - Equihash 96/5 memory requirements are rather low for a GPU only coin. 

I will write some FAQ lines for this during this afternoon. Or hurry implementing the multi GPU one instance use ... or better both