Well the oh-so-obvious retort is "well lets go somewhere less public then" at which point your back to hers or yours for a shag. This poor girl did her absolute best to hand it to you on a plate I mean FFS how much more obvious could she have made it.

To convert a sentence from chick speak into blokes language all you do is change the negative clause to a positive and then change everything else to its opposite meaning to compensate, in this case:
"I don 't kiss people in public"
I don't -> I do
public -> private
people -> you (general to specific)

Thus she was actually saying "I want to kiss you in private".