Yes, I always insist on being attacked only by acceptable people who conform to my standards ; -). otherwise I refuse to get involved.
FWIW, if we're talking about self-defense, learning to pick and choose who you hang around with or allow to get in your physical personal space IS just about the single most important and powerful thing you can learn. Far more likely to save your life than the actual physical fighting skills.
That said, I don't think that's really what's going on here, from the sounds of it. More of an aside.
But hopefully the OP can find a way to resolve the situation so they are comfortable and getting a good training experience. I wonder if there's anyone at the dojo (sensei or another student) they know a bit better or feel more comfortable with they could ask about this? Maybe people aren't aware how much they're doing it -- presumably the sensei is probably interested in things that might make newcomers feel more welcome and be more likely to stay. Or alternatively maybe there's something the OP could do to differently, e.g., smile and approach people more (just an example since someone mentioned sometimes people get the impression someone's reserved and would rather be left alone). Or maybe this just isn't the best fit of a dojo, also possible.