I am still following this discussion with great interest (despite being accused of placing irrelevant remarks..)..
While personally I can not contribute much - the lack of deeper understanding of the subject (mathematics - mine is on the engineering level, more than enough for what I do professionally but totally in-adequate for going deeper into GR) prevents me from making any statements apart from general ones (which I did earlier), I did some research among people who know the stuff and who-is-who (one friend of mine is in this subject up to his neck, if not deeper) and he confirmed for me that plasma effect on light bending WAS taken into account, during original experiment/measurement... That is why this discussion is pretty meaningless. As it is meaningless to take this author into account too seriously in general ("Only I understand and see what is going on here, all the others were stupid and blind..." which is what he is saying in essence, cherry-picking the experimental results while not describing in detail the methods used, which suggests to the average reader that measurement results were misinterpreted in haste to prove relativity.. which is very far from the truth..... and he is doing exactly the same, only to disprove it. In my book, this is not very scientifically credible approach.. )
Also, for the experimental confirmation of effects of gravity to EM, have a look here:
http://hyperphysics.phy-astr.gsu.edu...iv/gratim.html
In the meantime, I am trying to find gravitation simulator (Einstein's ring issue) on the web, which is based on relativity.. I stumbled on it quite some time ago, but I lost the link.
If this simulator is producing the same images as seen in reality (and as I remember it did, quite so), then we can forget about this guy, IMHO.
EDIT:
This is not quite the same website but it will do (simulator is very simple, it uses only one, pointlike mass.. the clusters of galaxies are - as we know - distributed, so the images they produce are much more complex than shown here in simulation):
http://www.astrophysicsspectator.com...sPointSim.html
also:
http://www.astrophysicsspectator.com...ldLensSim.html
http://en.wikipedia.org/wiki/Einstein_ring#A_simulation
http://www.photon.at/~werner/bh/gvsim.html