Theism has managed to kill an estimate of 2,229,074,100 people.
Atheism has managed to kill an estimate of 95,000,000 people.
So the best source you can give me is "atheistblogger.com"? Okay. Let's have a look at what atheistblogger.com says and what evidence he provides.
First on the estimate that atheism has killed 95,000,000 people. He gives 20 to 40 million deaths for Chairman Mao's regime in China. The Black Book of Communism
gives an estimate 70 million, part of 94,000,0000 with a small margin of error for the entire history of communism, though being published in the 90's it doesn't include the most recent communist atrocities. The Black Book
is famous for its exhaustive documentation. However, we should also remember that there have been atheist tyrants who were not communists. (For example, Alfonso da Costa, head of secret police in Portugal for 18 years.) However, I imagine that sum total of murders for that group is relatively small compared to the total for communists. So I'll accept the 95,000,000 figure for our purposes.
Now let's consider his tally of supposed theist atrocities.
The first example he gives is the An Shi rebellion, which he claims cost 36,000,000 lives. He links to a Wikipedia page which explicitly says that it almost certainly did not cost 36,000,000 lives. Oops.
He says that Genghis Khan was "an avowedly religious person". He links to a Wikiedia article which says that we don't know much of Genghis Khan's religion. Oops.
He says that "Total violence between Protestants and Catholics over disputes of religious ideology in the Middle Ages have been conservatively estimated at 14 million." He backs this up by linking to a page that says nothing whatsoever about the topic. Oops.
(Also there were no Protestants in the Middle Ages. Oops.)
He mentions Japan in the sixteenth century but his link is to an article that says nothing about religion in Japan at that time. Oops.
He claims that the Crusades cost 9 million lives. His link that supposedly backs this up goes nowhere. Oops.
He blames Christians for the death of 100,000,000 Native Americans, then links to a page that specifically argues against
blaming Europeans conquerors for those deaths. Oops.
He says that the Puritans wages "biological warfare with smallpox-infested blankets" and links to a webpage which says nothing whatsoever about that. Oops.
(Also the smallpox epidemic had already spread across the Americas before the Puritans arrived. Oops.)
And there are many other "oops" moments on that page, but I lack the patience to list them all.
At the end he gives a "final tally for theism" of 2,229,074,100. Unfortunately for him (and you) even the phony numbers that he's presented throughout the page do not add up to that number. Oops.
So, are you still willing to claim that "theism has managed to kill an estimate of 2,229,074,100 people", or are you willing to admit that you got fooled by a bogus estimate?