Well, actually commenting on the original topic of this thread...
To say that Egyptian religious rites and symbols have parallels in Christianity (and that is a valid statement - Osiris was being worshipped long before the Jews were enslaved by Egyptians) is perfectly legitimate, especially considering the statement I have in brackets. The Jews, who are essentially predecessors of Christians, spent a great deal of time (I don't remember how much and I don't have a Bible handy) in Egypt, so it's pretty safe to assume that the Jews would have picked up some Egyptian customs and rites and incorporated them into their own lives and beliefs. This also happened when the Romans created Catholicism. Most Romans worshipped the Roman pantheon (which had adopted Gods from the Greeks and Egyptians, to name a couple cultures), but Christianity was on the rise, becoming popular very quickly. The only problem with Christians is that they only believe in one God, and won't accept other gods, and while there were no laws prohibiting worship of any god, Roman law did not accept the persecution of other religions by any one religion. Christians were quickly becoming a problem.
So, to solve that problem, the Roman Emperor Constantine and his council created the Holy Roman Empire, a Christian state. Polytheism was abolished. However, to make the general populace comfortable with the idea of Christianity, all of the major pagan holidays were incorporated into Christianity and given Christian names, ie. Winter Solstice = Christmas.
So, you can see how parallelism between different cultures and religions is very common and often logical.