“know and love” is a fixed phrase - the love isn’t literal - the whole phrase just refers to something/someone very familiar (even sarcastically if you don’t really like it): “LingvoLive is launching a new interface next week. Gone are the hearts that we know and love.” (= the hearts that we’re all so familiar with)

A very common and humorous/sarcastic way of expressing that someone has changed so much that you don’t know them anymore: https://www.urbandictionary.com/define.php?term=Who%20are%20you%2C%20and%20what%20have%20you%20done%20with