Repository data is LICENSE free, use it as you want at your own risk.
You cannot retroactively revoke permission you already gave to people. Only if this sentence were removed, then without a LICENSE the content becomes proprietary from that point forward, and permission would be needed... but the repo state as it is while this sentence still exists, makes it free game for everyone.
From your own README:
You cannot retroactively revoke permission you already gave to people. Only if this sentence were removed, then without a LICENSE the content becomes proprietary from that point forward, and permission would be needed... but the repo state as it is while this sentence still exists, makes it free game for everyone.