This is just friends telling their friends that their photos are nice. Why are you looking into it so much, are you so stupid or anti social that you never heard people compliment things they really shouldn't?
Yes not everything and everyone is beautiful but we all like compliments even if they'r not 100% authentic or from people who shouldn't have an opinion on that subject. I love cooking for example and when I cook for my family who's incompetent in the kitchen I always get praised even when the food is average. Unless I majorly fuck up they will alway say it's good, just fucking human nature. You guys don't get to experience this aspect of life because the tv/computer screen doesn't have any emotions.