You & Me . . . and the Peanut Gallery?

I recently came across this video via a Youtube suggestion.  Aside from my questioning my search history (what puts that title in my suggested videos?), it got me thinking.  I watched it, and a few of their other clips.  Honestly, I found the couple to be awfully adorable.  "Who cares if they aren't the same age?" I wondered. According to the comments, general societal consensus, and the fact that they had to make a Youtube channel and a website for themselves and others in age gap, or what they call May-December (representing the "spring" and "winter" of one's life, as shown in the two member's differing ages).  

I've asserted for years that I'm going to grow up and marry Prince Harry (stay tuned for my adventures in England next spring!).  With an eleven-year age difference, I got a few sidelong glances and snide remarks, but my comments were generally dismissed as a childish crush.  But why not an eleven-year age difference (ignore the fact that he's royalty for a moment)?  If the couple is made of consenting adults, then whose business is it besides theirs if they are in a relationship? 

I could get technical and pull out the "age is a social construct, and therefore. . . . " but I won't get that into technicalities.  My question is simple:  why should it matter?  After all, if we're talking about two (or, heck, more than two) consenting adults, is it anyone else's business if they want to be involved, romantically or otherwise?  No.  Of course it isn't.  

The same can be said for same-sex marriage, no?  It's no one else's business.  If it's not hurting you--- and I mean legitimately hurting you, not some version of personal offence --- leave the people in question alone.  Admire them for finding romance in a world of justified cynicism.  Let them be in love.  

After all, love is pretty amazing.  Why would you keep anyone from having a chance at it?