Are you implying that the Ashkenazim are more welcoming?
I agree with Wallflower. Ashkenazim run most Shuls and Yeshivos. Part of getting used to America is getting used to our Shuls. An Ashkenazi rarely enters Sfardic Shuls, and feels lost.
At one point I Davenned Mincha in a Sfardic Shul. I didn’t know of their Minhag (that the Beis Yosef alludes to but didn’t like) of the short Shmone Esrei. Obviously, I was out of place.