Yeah, I don't know where the user you replied to came up with that, but this moment is nothing like watching "animals behind a glass pane", and the fact that /u/zibbers1 thinks the reason this has so much attention is because people view the couple in the gif as "animals behind glass" is really bizarre to me, and also pretty misguided.

While I watched this I was moved by how much the guy clearly cares for his wife, and it also made me think about whether I'll ever feel that much love for someone. Now I don't know about zibbers1, but when I go to the zoo and look at animals behind glass, I don't typically wonder if I'll be able to have what the animals have some day. People aren't watching this and going "oh wow look at the old people acting just like humans!"

And even if the recording was taken without their knowledge, it's just a guy caring for the woman he loves. It may be a private moment between them but it's warm and beautiful and is being shared for those reasons, not because people think "old people are animals behind a glass pane that you should get excited about when they do nice human things" I still don't understand what the hell that is even supposed to mean.