The wise man didn't actually say that he should blame his tools. The wise man had said, "If your work is bad, blame the wind."
So both saying were ridiculous and meant that he should shift blame, preferably to something that couldn't speak up for itself. Loki was just appropriating the adage and making it more suitable for his current situation. In this case, he was blaming lifespan for being a poor form of energy.
To be fair, blaming lifespan wasn't baseless either. According to the schematics, he should need a higher grade of energy. So lifespan wasn't entirely blameless in this matter.
Unfortunately, he didn't know what that higher grade of energy was. The Gemini younglings also didn't know what's higher than lifespan. To them, lifespan is the highest available energy. Apparently, this was because the quality of lifespan improved with the strength of the lifeforms using it.
