I'm a little puzzled. Are you all saying that you never loved your parents, siblings, pets, etc.
In a way, but not quite, just different perhaps. If you do the medical research on the topic of "autism and oxytocin" you will find that many of us, due to issues with the hypothalamus-to-posterior pituitary signaling, may have abnormally low levels of this hormone. Oxytocin and vasopressin are known as the "love hormones" that are released during interpersonal bonding. It's, in part, the euphoric feeling one gets when you meet that special person who you just "click" with and want to be around all the time because of that feeling. It is also, in part, responsible for the motivation to meet with people, introduce yourself, seek companionship, and perhaps even feeling energized and better when you are interacting with people. So many of us, feel quite the opposite in this regard. Socialization becomes a negative thing because it drains us of our energy and frankly, some will need a day or two of rest and recovery after a stimulating social experience.
Now throw in alexithymia, another common comorbidity with autism, and you have a situation were either there is an unawareness of emotional states, an embarrassing and inappropriate 100% ON/OFF of emotion, or an internal fear of emotional dysregulation and a constant squelching of emotion that, over time, leads to a general state of emotional neutrality, as it is deemed "more safe". Q.
"What are you feeling right now?" A.
"Absolutely nothing."
Having said that, the bonds that we have with our parents and siblings, even our spouses and children, are, I suspect, not at the level of intensity that say, a neurotypical would experience. Furthermore, as
@thejuice commented, unless there are positive bonding experiences on a frequent basis, love is conditional and fades over time. They just become people in your life, or past life, and there's no looking back. Water under the bridge. There is little, if any, need or wanting to rekindle a faded relationship. You don't "miss" people.
So this gets into a few contributing reasons why some of us are so frustrated, even angry when it comes to relationships.
"How come I can't make friends?" "I want a girlfriend, but don't know how." "I want to know what love is." "Nobody likes me." "I am going to be single my entire life." So on and so forth. It's not for a lack of desire. Whatever is supposed to happen in the brain during interpersonal interactions, key things are missing and bonds are not created. Autism = "auto" or "self", "
One who walks alone." Even whilst being married, in every other aspect of my life, I often sense that I walk alone, there but not there, out on the periphery, seen but not seen. Most people are just things/objects to navigate around, pretty much in my way all the time.
My wife and I, are life partners. We do everything together. We hold hands and cuddle on the couch. My children are grown and have their own lives. I do enjoy seeing them. However, even when they were at home, there was always a "glass wall" between us. They sensed it. I sensed it. We still sense it. I don't have the words to explain, but we have never really bonded in what I would consider a "normal" way. They were good kids. There was never any emotional or physical abuse in the way. We were quite generous with them. They would bond with my wife, and not me. If there was a problem or something needed fixing, they came to me.
I get a bit of emotional attachment even to things like frogs and lizards that I see out in the yard frequently. Should I seek a second opinion on my diagnosis? There were so many things that did fit like special interests, infodumping, sensory issues, and stimming. 
