Even most introverts and loners(if not all) crave social connections, having at least a friend, a loved one, feeling connected.
It's like, we all need the same things at the core but how that need is met differs. We all need food, for ex, but we don't all need the exact same food or amount of food and some are allergic to different foods. Our bodies need exercise but while some of us jog, others walk or play a sport or do a nr of those things.

Point is, just because the way we fulfill our needs differs, it doesn't mean the need isn't still there. All animals(or most creatures at least) will seek shelter, food and procreation but shelter means different things to different creatures, same for the other needs.

There's solid and long term research that shows human beings will in general suffer different negative consequences, to some extent or another, some more visible than others, when their need for belonging, connection and intimacy isn't met(whatever that quota happens to be in each case). This is something observed in other social creatures as well and it makes total sense because we have evolved to need these social bonds as they are key to our success as a species.

Oh and there are always exceptions to a rule, that doesn't invalidate it(or mean that the rare exceptions are somehow wrong, just different).