I was alive at the time. While there were some protests, i dont recall them being all that significant, and many of the objecting voices seemed more concerned with the price tag rather than the human cost.
https://web.archive.org/web/20040904214302/http://www.guinne...
Some estimate that these were even bigger than the demonstrations against the war in Vietnam in the 1960s. These put the total number of people going out in demonstrations world wide at 30M+. This war was massively protested against, any which way you count.