When I equated creationism to racism and homophobia, what I meant was their scientific application and understanding.
Racism existed because certain groups of people thought they were inherently, biologically better than others. This is scientifically false.
Homophobia exists because a group of people decided that homosexuals were inherently worse than straights. Again, there is no scientific basis for this opinion.
The same with creationism. It goes against what we know of the world, what we've learned through science.
Thousands of years ago, it made sense that God or Gods created the world because we had no other way to perceive what was going on around us. The more we learn, however, the less weight those kinds of opinions hold.