Pets can love you back. The same isn't necessarily true of most people.
My dog only sticks around because I feed it. But then that's the same for my partner.
I suppose you could say its some kind of need for companionship? For me and my partner that's evolutionarily good for raising our spawn. But my dog has been genetically bred for 1000s of years for our purposes, maybe for a dog, it's unnatural to love, and a form of genetic enslavement? Maybe they've just learnt they get rewarded when they show 'love'.
Of course theres also the chance that you're anthropomorphising an animal.
There are ways to have a symbiotic relationship with another animal without strict verbal communication. Maybe you just haven't taken the time to learn about your animal and the things that make it unique and worth loving. Because it might already be doing that about you.
I know I wake up every morning to my cat purring on my face and nestling into me and she starts purring the moment I pick her up. She's not sticking around for table scraps.
I used to own rats. If you want to really learn just how emotionally intelligent pets can be, get a pair of those. Some of the most social creatures you'll ever meet.