Things being done "in the name of" God do not count as a complaint against Christianity.
There are the things people did in the Bible in response to direct commands God gave them, even down to small things like throwing staffs on the ground to prove a point in Egypt. God is infinitely just/right/correct, though, so even those cases don't make valid complaints.
But we're not talking about those. We're talking about the things people do "in the name of" God, which directly contradict the teachings God gave us, accomplishing the very opposite of what God instructed of us.
There's no need to even make a long post about it (though "long" is subjective - this post may be a novel for you), the truth here is simple - the complaint makes no sense. If I committed some horrible crime in your (the reader's) name, based on some intentional misconstruing of your words to fit some faulty interpretation to fit my own agenda, would you be at fault? Is it your fault that I, let's say hypothetically, used a post you wrote about rooting or a sports team, and twisted it to be a metaphor for supporting the absolute genocide of every person who doesn't live in my immediate area? Of course not, and that's not the case with God, either.
May God bless and guide you according to His perfect will. In Jesus' name. Amen.