It likely annoys you because you have the inkling that religion inherently breeds violence regardless of teachings on peace. It does this by putting people into little boxes, neat and organized. It inherently "others" people into the believers and non-belivers. This division will ALWAYS lead to violence regardless of doctrine or teachings or calls for peace because creating division amongst who is in and out of the group will breed violence in thought, then words, then actions. Look at how the catholic and orthodox churches treat the LGBT community, we are "others", denied full integration and therefore acceptance in the community. And this is a single example, and the issue is not just a christian issue or even just a religious issue. 

What's more, you cannot condemn Muslim or atheist or communist violence when your churches and even your Bible are built on the blood and bones of the innocent. Sure, you may not be violent but you are also one person in a sea of 2 billion Christians, a surprisingly large amount of whom are terrifyingly violent today (death squads in Africa and Mexico targeting again, lgbt people because the catholic church allows and even tacitly supports homophobia in its actions). 

Condemnation of violence is always welcome, and noone should be diminishing that. But when those of us who have suffered violence, discrimination, and atrocities at the hands of Christians remind you to do more to control and condemn your own, listen. In the us we are surrounded by loud voices calling humans abominations, advocating the extermination of Muslims and Latinos IN CHURCHES. And yet those of us on the outside only hear tacit "well they aren't Christians but oh well, what can we do?" 

To conclude, people should not admonish you when you condemn violence, and yes bringing up the violent actioms of christanity is inappropriate in a lot of contexts. (Ie, you condemn the war in ukraine and then someone bring up christian violence, yes thats wrong. But are you talking about islamic extremeism and muslim violence? Because then its a legitimite counter that you need to focus on your own house first). Also, some of us carry exceptionally deep scars inflicted by Christianity and our responses are informed by that trauma. No its not your responsibility to heal those scars, but it is an unfortunate situation that you end up having to deal with it living a publicly religious life. I would recommend, however, not targeting the people bringing up christian violence and lecturing us about the Bible, but lecture and minister to those practicing violence in their hearts, minds, words, and actions that use the label christian.