Who I maintain relations with and who I don't is not other people's business similarly who I follow and who I don't follow should not be visible to anyone except me but that is not the case.
I can go on and on about similar things but the bottom line is everything on Instagram is designed in a way such that it generates more activity on platform and ultimately more revenue. This is true for almost all the social networks though. A social network that respects norms of our society and does not attempt at maximizing revenue at users expense will probably fill the void left by the existing ones.