Link blocks and Div Blocks Exhibit Different Stretch Layout Behavior

Div blocks respect the stretch layout of a parent container, but link blocks don’t. Why is this?

Example:
If multiple divs (default set to block layout) are within a container that’s set to flex layout and stretch alignment then the divs stretch to the longest length div in their row.

http://www.giphy.com/gifs/lQZvvM7FxZ11O2bs28

Link blocks don’t. They must be set to flex layout and stretch alignment themselves for the element to stretch to match the longest length div in their row.

http://www.giphy.com/gifs/LOtLUHbteU40pnvJZK