Macroevolution may, or may not be true.
So do you believe in "microevolution?" "Macroevolution" is just "microevolution" at a larger scale. It is easier for people to accept "microevolution" because it's easier to comprehend small changes take place in a specie. Now extend "microevolution" over huge time periods and you end up with "macroevolution." It is not "intuitive" for humans to think on such large time scales, and there is no way you could reproduce something that takes tens of thousands of years in a lab. Some people will take this as evidence against "macroevolution."
Check that URL I posted in my previous message. It does a fine job showing some of the transitional types that have been found in the fossil record, as well as explaining genetic anomolies that could only have been caused by evolution. Special creation would not have resulted in a mutant, non-functioning "Vitamin C" gene in primates/humans, for example.
How many people really understand general relativity? Time not flowing at a constant rate is counterintuitive to most people. Yet most people don't have a hard time believing it... even before they know there have been tests to confirm time dilation.
The real reason people have trouble accepting evolution is because of the implications: that God may only exist in our minds.