Idk, there are two thoughts I have that lead me to a different conclusion than yours.

The first is even if she weren't gay, most parents wouldn't like the idea of their 19 year old kid marrying someone they've only dated for a year, and visited only briefly on the weekend. The "met online" part I don't get though. Online dating no longer has the stigma it had in the early 2000's. It's actually normal with things like tinder.

The other thought I have is that educational stipends are very normal for parents that can afford them. Your kid is going to college, you don't want them to have to split their focus between a part time job and their classes, so you give them a stipend for food and expenses. I was on the same thing.

According to OP he told his daughter from the start that it was money for college. But since she isn't going, there's nothing preventing her from finding a job (unless they're planning on raising kids very soon.)

I don't see how it's glaringly obvious OP is homophobic, for the reasons I've stated. I kind of think that's an unfair assessment to make based solely on what OP said.