Homer Barron, the first real beau of Emily Grierson, stuck out "like a sore thumb" in the town of Jefferson for many different reasons:
First, he was a Northerner, which was reason enough for the deep Southerner Jeffersonians to dislike him. To top it all, he was quite charismatic, loud, brash, and rogue. He spoke his mind and did not care about the mannerisms and propriety expected from people in the South.
Second, he liked his drink. He would drink with younger men in the Elk club.
Finally, let's face it: What is HE doing with Emily, the town's oldest vestige and a woman whose last name makes the old folk shudder due to its history and formerly aristocratic origins. This alone was reason enough to consider him a bit weird.