Why are these two women kissing each other in public?

Because they're attending a pro gay marriage demonstration in Paris, France, that's why.

Held last April 23, the "oui , oui, oui" (yes, yes, yes) movement gathered supporters outside the French national assembly in Paris.

France's lower house National Assembly on the same day adopted a bill legalising same-sex marriages and adoptions for gay couples, defying months of opposition protests.

source: interaksyon.com