Why do colors appear washed out on macOS Chrome and Safari versus Firefox?

I'm using a new MacBook Pro 15" with macOS 10.13.4 configured with the default Color LCD color profile. I'm doing some graphic design work and noticed that all colors in Chrome and Safari appear "washed out" when compared to Firefox. The latter has more saturated/vibrant colors. And this happens to native HTML/CSS elements (i.e. not images only). Here's a screenshot of the SmashingMagazine homepage with the comparison (Chrome on the left, Firefox on the right). Notice how the colors are more vibrant in Firefox (right): If I change my display's color profile to sRGB IEC61966-2.1, then both Chrome and Firefox look the same. Why is this? Any help is greatly appreciated.