Other than saying yes to joining a group, or begging for others to join yours you didn't. As for raiding, something like 5% saw raid content in Vanilla so it's not like many were completing content.
Yes, it's easier to get into groups and it can be done without "socialization"(again, that is not what has been meant over the last 10+ years of complaining about the lack of it). That still doesn't prevent players form being social once in those settings. Players would rather not. Again, players didn't really do as much as people love to claim.