I disagree with your post about Mithrism I have done extensive study on the religion and there are major similarities in the two regardless if Christians Borrowed from Mithraism the worship of Mithra was well established before Christ's birth. The websites you quote in your other post are all Christian based sites that seek to distance Mithraism from Christianity and have a philosophical ax to grind with any hint that the two religions share any common ground. That just isn't the case as anyone that rationally looks at history can show you.
I will say that the thought Mithra died for Mankind is wrong he actually killed a bull for mankind and according to Mithraism will kill another on his return to Earth to impart immortality to man. His death was more a return to Heaven. In fact we get the idea of seven Heavens from Mithra, the pearly gates come from Mithraism, I also believe the traditional winged angels and Halos are part of Mithraism as I have seen them depicted in Mithrireaums (Sp) or temples of Mithra.
The specific historical facts cited by those sites in refutation of the common claims regarding Mithraism are either true or they are not true, persuasive or not persuasive, regardless of the philosophical slant of the sites. You'd do well to disprove their evidence in the specific rather than dismiss them in general on the basis of what you perceive to be their suspect motives.
In other words, show us where these sites have erred as a matter of historical fact. Your extensive study of Mithraism would come in handy in such an effort, I would imagine.