You are comparing the historical reality of one religion to the ideals of other religions. In such a comparison the ideals will always look better. If you compare the ideals of Buddhism with the historical reality of Christianity and Islam (war, slavery, genocide etc.) I'm sure Buddhism will look better.
You will typically see people compare the ideals of their own religion with the realities of other religions and come to the conclusion that their own religion is best. The imperfect reality is explained by flawed people misunderstanding or misusing the religion, while the real-world problems of other religions is attributed to faults in the religion itself.