Grounding the Through Hulls?

[rbrasi]

I've removed all the old through hulls on my boat and before I did, I noticed that they were all connected by an apparent ground wire. I'm assuming it's ground because they were A) Green and B) leading nowhere but to each other and the strut bolts. Can someone enlighten me as to the necessity of these? I've included a picture from the galley, head and scuppers.

Edit- I just read an earlier post on this issue and discovered why this is. Sorry for the redundancy.