"With repetition, it's very easy to make new friends."*
*Assuming you possess the necessary social skills.
I've trained BJJ consistently for over 4 years now. I think fondly of all the people there and feel accepted, but we barely talk, and I'm unable to participate in the locker room camaraderie.
This is probably not a problem OP has, I just felt the need to complain.
I think social skills are mostly just like any other skill: you have to practice them to get better at them. And while you might be more or less naturally gifted at any skill, there is a minimum level which every abled human out there can reach with some effort. You will never be a showman,a car seller or the king of the party but you can have interactions with other human beings and connect with some of them. Just like you can learn to play guitar, juggle 3 balls or do basic algebra.
The other people probably just think of you as some stoic guy and respect you for that