I'm not sure what you mean by "historical globalization," do you mean the process underway since ancient times and increased by the Age of Exploration? Or are you concentrating on the modern Thatcher-Reagan model? There have been many problems involving both, but the process throughout history has been overall pretty positive until the modern version. The modern International Monetary Fund-World Bank and international corporation/bank driven version has been disastrous.
The slave trade has been with us since the earliest civilizations, and doesn't seem to be going away. People like to blame Europeans, but it was the Arabic countries and India which mostly ran the trade and absorbed nearly all of the slaves throughout early modern times, right up to today. Abolition began with the Methodists in Britain and gained strength throughout the 19th century, culminating in the theoretical ending of the African trade by the turn of the 20th century. Unfortunately, there are probably more slaves living in the world today than in all of history combined. In this area, we have moved steadily backwards since the 1970s. I'm not sure what a tribal war in Rwanda had to do with globalization, unless we consider the fact that both tribes were in one country because of Europeans drawing arbitrary boundaries for African countries with no regard to who actually lived there. I suppose we could consider the Berlin Conference as a 19th century globalization measure, but I'm not sure a border between those two tribes would have prevented the genocide.
Economically, the IMF/World Bank domination of countries by credit (the Thatcher-Reagan model) has been terrible in its effects on the economies of the world. The massive interest payments are difficult for most countries, and the conditions of the loans (deregulation of industries, forced sale of national gas, electric and water utilities and natural resources) actually make it more difficult for the countries to make the payments. The sale of utilities to consortiums of Euro-American corporations destabilizes the national economies, causing rising prices for power, water, and commodities, but not increasing wages.
In addition, modern globalization has wrecked the economies of developed countries by moving jobs to the Third World, while those jobs are not replaced by newer industries, due largely to the hold on the political and economic life of developed countries by the same corporations that move the jobs out. These increased jobs in the Third World have not raised wages in those countries as much as prices have increased, and while credit went wild in developed countries wages became moribund, complicating the loss of jobs.
Historically, the negative effects have been Europeans carving up the world for their own benefit, and they are today paying the price for this as much as anyone else. America added to the problem in the 20th century, thinking we were helping the world while only being manipulated by our largest industries and banks.
Globalization as implied in the question above definitely had some negative aspects. Whatever the causes and justifications of things like racism, slave trade, and environmental pollution, that happened in the past, There is no justification for these in the present. What ever remnants of these historical legacies are present in the world today, should be routed out by sincere and concerted efforts. Also we should guard against tendencies for such things to develop today in our highly globalized world.