There is a huge difference between Christianity and those who claim to be Christians and doing things in the name of Christ. People who call themselves Christians and go about killing others and promoting hatred are NOT behaving as Christians. They are merely using Christianity as an excuse to justify their actions. Therefore, it is wrong to claim that Christianity is responsible for more suffering to humanity. Not everyone who calls themself a Christian is one. There is the Red Cross, the YMCA and YWCA. There are Christian aid organizations which build homes, hospitals, schools, clinics and feed thousands of starving people. Many Christian churches will give some sort of benevolence assistance to those seeking help in time of need - even if those seeking help do not belong to that church or even believe in God. The basic principles of Christianity involve love toward one another, kindness, mercy, compassion and service.
If someone is doing hateful things or harming others and they say they are Christians, a person should be able to look at what Christianity really is and measure those who are hurting others against the standards of Christianity. If those doing the hurting are not measuring up to the standards of Christianity, then it is unfair to judge Christianity as a whole because of those individuals who are NOT Christians in practice (or possibly even in their hearts), but are merely using the name of Christ to further their own evil agenda. Does this make sense I hope?
As for swastikas and Nazi symbols, they flat out represent hatred, prejudice and intolerance. It is no wonder these symbols are illegal in many places. The Christian cross on the other hand is a symbol of a perfect love that is SO sacrificially loving, that the One demonstrating that love stepped down from His rightful throne in Heaven to become a Man and then died a horrible death on a cross OUT OF LOVE just so that all mankind who accepts His gift, could go to Heaven without having to earn their way there. THAT is what the cross stands for - love, sacrifice, giving, compassion, mercy. If anyone uses the cross as a means to justify hurting others, then they are NOT representative of Christianity, but rather of a wolf (evil) in sheep's (good) clothing. People really shouldn't judge all of Christianity because of these wolves.