Generally a author has copyright over their works without having to explicitly says so. Saying "Copyright (c) YYYY AUTHOR NAME" is just a way of asserting it to remove potential confusion or ambiguity.
With no licensing, there is no right to use a copyright work (except fair use). BSD licensing a work is granting permission is a set of circumstances, not revoking permission. Thus if a license is not correctly applied the work cannot be used, rather than the inverse.
As for "The content in this repo is BSD licensed" - the usual licensing wording is again a convention designed to be as clear as possible, but the wording applied there probably counts as it pretty clearly intends to give permission. The "probably" is why people ought to stick to known and understood conventions.
Comments
(IANAL, most familiar with UK rules)
Generally a author has copyright over their works without having to explicitly says so. Saying "Copyright (c) YYYY AUTHOR NAME" is just a way of asserting it to remove potential confusion or ambiguity.
With no licensing, there is no right to use a copyright work (except fair use). BSD licensing a work is granting permission is a set of circumstances, not revoking permission. Thus if a license is not correctly applied the work cannot be used, rather than the inverse.
As for "The content in this repo is BSD licensed" - the usual licensing wording is again a convention designed to be as clear as possible, but the wording applied there probably counts as it pretty clearly intends to give permission. The "probably" is why people ought to stick to known and understood conventions.