[cakoose]

> It's therefor also fine if you're writing in a monospace/fixed-width font.

This is the standard explanation I see everywhere, but I don't get it.

With two spaces, the gap after a period is longer than a gap after a comma. Why is that "obviously fine" in fixed-width but not in variable-width?

[lamontcg]

> With two spaces, the gap after a period is longer than a gap after a comma.

As it should be. A period is a full stop, not a continuation.