Does "a" not mean, one out of many in this context? I know English is not my first language, but I've always taken "a reason" to mean one of many.

You said:

> there is a reason

What's in the garage? There's a car. I wouldn't expect to walk in and find many cars.

Had you said:

> this is a reason

that would convey it was one among potentially many.

Either way my comment wasn't even about you, it was about Reddit, so idk why you got riled up.