Grill blocked for the first time (Phoenix)..questions

Since all I saw was the light gray stuff too, I ended up running a strip of narrow black tape between the outermost vertical supports. The other vertical supports keep it from collapsing too much. It lets a little air through, but a little air is okay, especially if you block all of the lower grille openings with it.

Only took a few seconds and not much tape. Might not work well in a wet snowy climate, but seems fine for here in the sunny southwest. If it collapses, maybe I will replace black vinyl tape with black cloth tape (like you'd use on a hockey stick handle). Or stuff in the grey insulation and cover with the tape to hide it.