Calm down folks.. you guys are making me nuts here.. We are talking about a pedal incert, it's going to fail due to mechanical deformations by the cleat, not surface treatments. It's not like this thing is going to rust away. Right!
Ok, so I did the leg work for you guys. Here's the jist of it.
7075 is correct in some points. Anodizing does increase the surface hardness, and thus more prone to cracking and stress induced cracking.
But under normal tensile mode, not bending or twisting to induce cracks, anodizing positively affects the tensile strength of the 7075-T6 alloy.
Here's the referance..
Singh, Vakil; Rao, Vinnakota K.; Rao, Palle R. Zeitschrift fuer Metallkunde (1976), 67(4), 235-40. (journal is in english)
Now, Superlite, is also correct. Improper treatment will cause a decrease in fatigue life. Especially with the wrong acid treatment (cleaning). That should be obvious, but here's the referance.
Stickley, G. W.; Lyst, J. O. Alcoa Res. Labs., New Kensington, PA, Journal of Materials (1966), 1(1), 19-33.
So what does all this mean. It means for 7075-T6 alloys are improved with anodizing when the parts are strucural. Why, because A) it looks better B) it prevents further unwanted oxidation which leads to premature failure. To be honest, for the part in question, you could leave off the anodizing or put in on, it won't matter. The part will fail due to mechanical deformation by the cleat, long before a oxidation mechanism will cause failure. That's providing you don't soak these things in warm salt water, in which case anodizing will help.
To make 7075 feel better, stress induced cracking is likely why spokes aren't made of Al. Twisting and bending of Al is a bad thing, especially when anodized.
Nothing like a little argument to get the off-season blood moving.