Sincere pet question...

While I have never owned a pet in my adult life, that doesn't mean I would never. I very much love animals and I know they make great companions! I am very fond of horses, and plan to own a few when my farm is finished.

But aside from the messes they make in the house (hair everywhere on bed, clothes etc, odors, urine, feces, litter boxes, bad breath, tearing up stuff)....

What is the obsession with or why do pet owners allow their pets (mainly dogs) to lick them on the mouth excessively? I mean I get accidental licks. But open mouth, tongue all in there, straight up swapping spit. I cannot comprehend. Why is this a thing? Is this only an American thing? I see it all over social media! A peck I get. Maybe. But why the full on what is essentially making out? I could never imagine, and have yet to see, this occur with horses.

I am disgusted. Sincerely troubled.