How does any site in the US not run afoul of Americans with Disabilities Act (ADA)? Surely color choices like this are an issue that someone can raise; see WCAG

How does any site in the US not run afoul of Americans with Disabilities Act (ADA)? Surely color choices like this are an issue that someone can raise; see WCAG 2.0 AA. which talks about how there must be a color contrast ratio of at least 4.5:1 between all text and background. Even W3C reminds people that colors are important.