I think the consequences of science denial are huge and impact everyone in society. As a member of society, this affects me and it affects my children.
People who deny evolution are undermining the proper teaching of biology in our schools. They are undermining anthropology, geology and molecular biology - all of these sciences provide humans with a deeper and more complex understanding of life.
Denial of evolution means denial of the evolution of bacteria and viruses - which directly affects me. Creationists have worked in areas where their beliefs have caused serious harm to humans (think of Dr. Leonard L Bailey, whose rejection of evolution possibly caused the death of his patient, baby Fae).
I have an opinion about people who affect me and who cause harm or have the potential to cause harm to humans. Everyone does.