And how many Catholics were killed by Nero for sport?
Lets not change the subject. The question is did the Catholic Church cause people who it did not agree with to be killed? My answer is yes the Church did kill people who it did not agree with. The Cathars are a prime example cited by me. Lets not change the subject to how many Catholics were killed by Nero. Its not relevant to answering the question.
Such answer on your behalf amounts to what is often referred to as a straw man argument.
The fact is when the Catholic Church got a hold of temporal power it abused that power and killed those with whom it disagreed. The Cathars are a prime example.
Now if you desire to take the position that history is wrong and that the Catholic Church did not at any time in history cause people to die that it did not agree with, then you should start with disproving the historical facts regarding how the Church acted against the Cathars.
Now of course you might want to make the argument that the Cathars were proclaimed by Catholic Church as heretics, and thus it was OK for the Catholic Church to harm them. That would be an attempt at justification for the actions of the Catholic Church in killing Cathars because the Catholic Church did not agree with them.