The issue is not whether the colonial powers were brutal or not in the past. They were, but so has been most of human history. The issue is not whether they set or not a NEW standard for society where human life is dignified, a set of norms we can ALL live by. They did. The issue is not whether we can hold or not those principles as a measure of social progress. We can. The issue is that once we have accepted those principles, turning our back on them entails becoming reactionary. The issue is that applying AT THE PRESENT TIME those principles only to the privileged members of a society, or to some nations, excluding others, or to ignore them for convenience of the powerful and rich, therefore appealing to double standards, becoming cynical and hypocritical, using those norms as a mere PR stunt, directly contradict the principles themselves and the ethical stance of those who pretend to abide by and promote those norms.
So, no, the long history of barbarism does not justify the CURRENT ethnic cleansing carried out by Israel, nor the illegal occupation, nothing the Zionists have done for the last 100 years. Also, no, the long history of rule by force and colonialism does not justify CURRENT rule by force and colonialism. And no, having conflicting sets of values with the victims of discrimination, genocide, colonialism, etc., does not give the perpetrators the green light to CURRENTLY execute those crimes without the consequences of being denounced and prosecuted. No postmodernism, no idealism, just plain old consistency.
― Marcus Tullius Cicero