should be thankful that there is any fault of which one can be unjustly accused里的one can be...理解成one can "afford to" be...就顺了
举个傈子:
我指责你虚荣,你觉得unjust,但是你老除了面子上过不去并没啥损失;
但是你看看俺,被指责鸡奸,俺也觉得unjust,但是立马就要蹲大狱。
跟俺的遭遇比,我给你那些指责你应该觉得庆幸(thankful)才对
所以要我来翻,这句是 "如果你觉得有些指责失之公允,你应当庆幸你无须为这些指责承担罪罚"